The main difference between a pro and an amateur consists in having a clear idea of pre-flop ranges. Starting from that point everyone can set a certain strategy, which needs to be followed by a quality post-flop game. This section is meant to be a guide for beginners in order to explain the concept of "range" in poker and not least, help them to build up their own ranges according to their style of playing.
We need to know that in Texas Hold'em there are 1326 possible combinations of cards, which they become 169 if we exclude all suites. Therefore, just to make a quick example, they do exist 16 combinations of 7-8 (each suite combined to another one, 7♥8♥ 7♥8♦ 7♥8♣ 7♥8♠ 7♦8♥ 7♦8♦ 7♦8♣ 7♦8♠ 7♣8♥ 7♣8♥♦ 7♣8♣ 7♣8♠ 7♠8♥ 7♠8♦ 7♠8♣ 7♠8♠) but for our purpose, we just need to divide them into 2 main categories: suited and off-suited.
What we really mean by building up a range and why is it so important to master that concept? As it recently came to light in our talk with Alec Torelli about how Texas Hold'em has changed during last years (interview), what makes a real difference between the game played nowadays compared to the past is indeed the concept of 'range'. Having clear in mind which combination of cards are profitable to play in a certain position reduces automatically the number of mistakes we would do post-flop. Ranges need to be adapted to every single situation, depending on the position and the depth of the stack. In general, the more players we play against, the tighter our ranges. So, with all players equal in chips, we'll play a smaller amount of hands in a full-ring game rather than in a 6-handed phase.
Each hand we receive in Texas Hold'em has to be considered from two different prospectives: its effective value and its perceived value. For example, raising from 'Under The Gun' with 20 big blinds is perceived as a stronger move than an opening from the button, even though we're doing it with the same hand and stack. So, depending on our position at the table, the range of hands we would face when somebody decides to re-raise will be tighter.
The main goal for every player is being able to combine the strongest and the weakest part of the range in a way that our opponents cannot have a precise clue of which cards we're playing with and when. In short, thinking 'in ranges' means to assign a certain number of hands to the opponents instead of putting them on just one or two hands, as many players used to do a few years ago.
Many of you have already heard about Nash equilibrium. For those who did not, John Nash was an American mathematician who died last year and gave a fundamental contribution to the so-called 'game theory', a mathematical model applied to economics, logic, psychology, biology and of course, poker
Nash's rules aim to put the player in condition to win or at least not lose in the long run so, according to them, we need to build up the first sketch of what it will be our own first range-model. The distance between our model and Nash's parameters increases proportionally with the knowledge we have on other players' game. It would be a waste not to enlarge our opening range against a tight player as well as it would be a problem playing with a much wider range against a loose-aggressive one.
Here it comes another important matter: the concept of 'balancing'. In order not to be exploitable, when we make adjustments on others we must be sure to have balanced enough our moves. Even a tight player might be suspicious if we raise too often their big blind, therefore we should take care of not giving away too many hints about the range we decided to play against them. For the same reason, it has no sense to balance a move with unknown players: their choices would not be affected by the game history and every attempt to take a considerable distance from Nash's equilibrium would miserably fail in the long period. That said, let's start getting a bit deeper on the topic.
Building up a balanced range isn't easy at all. What we're going to try though, is to put everybody in condition to understand how to create ranges which suit perfectly to each one's game. Here we have a spectrum of all hands in Texas Hold'em, divided into suited and off-suited. As you may notice, on the bottom-left part we have all off-suited combinations and on the up-right part, we find all suited ones, while all pairs are banded together on the diagonal line from up-left to bottom-right. All hands are also sorted by strength: proceeding from up-left to bottom-right, strength progressively decreases. 

Hands Sorted By Strength

1: Analyze your game

There are a few things we must consider before getting started. First of all, we need to understand what kind of player are we. Not to get too deep into details, we can just divide into loose and tight players, according to the number of times we use to be involved in a pot (VPIP – Voluntary Put money In the Pot). Every action we do at the table entails a reaction from opponents: foreseeing all possible moves and having a precise idea of what to do in certain situations it will be useful for our purpose. Because ranges need to be adapted to our style, so it might be unsuitable opening from early position with a wide range if we already know that barrelling a couple of streets in bluff isn't really our thing. A tight player normally plays from 6% to 15% of all hands, while a loose one can easily reach 30% or more.


2 : Find crucial blind jumps. 

Sometimes there's no room to plan a hand on all three streets. Not just because of the amount of chip we have in front of us, but mostly due to opponents' stack, which might be short enough to put us in a tough spot even when having a good hand. So, we need to have clear ideas and choose with which hands we would like to raise, re-raise or face an all-in. Generally, the 'push or fold' line is around 10 big blinds, although many regulars nowadays use to raise and then fold even with 7 or 8 bigs. This kind of adjustment isn't really necessary at this stage, what's important for now is to identify three or four blind jumps: from 0 to 10, from 10 to 20, from 20 to 30 and over 30 big blinds. These parameters may be set up differently depending on the type of player we're facing and, of course, on our game style.


Phase 3: Dividing per position

Our ranges will be subjected to substantial differences depending on the position we occupy at the table. The closer we get to the button and the more we are allowed to increase the number of hands to play with. We're going to divide positions into six blocks:
Early positions: UTG, UTG+1 and UTG2 (only in 10-handed tables)
Middle positions: MP, MP+1
Late positions: Hijack, Cut-off
Small Blind
Big Blind
For each block we need to create as many ranges as the number of blind slots we decided to set up. Nothing to be scared of, though, it will be easier than it seems. 


Phase 4: Identifying the field

The last and probably the most important thing to consider is the type of field we are going to face. In low buy-in tournaments, we'll likely play against recreational players, which are normally inclined to, at least, see the flop before mucking the hand. Also, many players have gained enough confident to play a larger number of hands today, so that they use wider ranges than in the past.


The position is everything, or nearly.

Either a renowned professional poker player or an amateur, no matter what, they will always lose chips from the blinds and win from other positions. It's just math: we will lose at least one blind when not involved in the hand and we'll have to struggle a lot to win the hands with decide to play, simply because we're doing it out of position. Just for the records, hitting at least a pair on the flop happens more or less one out of four times: not tempting enough to play so many hands without being in position on other players. That's why we will use a wider range from late positions and a tighter one from early positions or from the small blind. Big blind deserves a separate chapter, mostly because starting from pros, many players in the last years  tend to defend as much as possible their blinds
For instance, we would likely avoid playing weak and middle Aces from early positions (A-2/A-10) because even when hitting the board we would have troubles due to our kicker. From late positions, weak Aces are welcome instead, since we don't necessarily need to hit anything to win the pot. And now we are ready to build up our ranges!

Tight players

Tight players have normally a solid game, which means they play mostly for value and rarely bluff on some particular board textures. In order not to check-fold most of the hands they're involved in, these type of players must be really accurate in the hand selection. With an opening range from 15% to 20%, we will have almost all suited Aces and most of the off-suited ones, some broadways, pairs, and some suited connectors (but only from late positions). Early position ranges will be really strong and they would not cross the 10% of all starting hands.
Early positions: Excluding all borderline situations in which we don't have enough chips not to be pot committed after the first barrel, with an average stack we should open suited Aces from A-J + and off-suited Aces from A-Q +, all pairs from 8-8 + and some suited broadways like K-Qs or Q-Js. Starting from that we can also add some more combinations, depending on how confident we are in the post-flop game. 
With the very top part of our range, like A-A K-K Q-Q or A-K, we might consider to re-raise a 3-bet. Tight players do not usually have a bluff range from early positions, so we must be really careful when we play a pot against them, even though we have the position on them.
Middle positions: From middle positions, we can extend our range to some more suited (J-Ts, K-Js, K-Ts) and some off-suited (K-Q, Q-J) broadways. We can also open more pairs (5-5+), all suited Aces (A-8s +) and some off-suited Aces (A-T +).
Late positions: From Hi-jack and cut-off we can use all suited Aces and most of the off-suited ones. All pairs are welcome together with strong Kings and Queens (K-T+, Q-T+), possibly suited, and some suited connectors (8-9+).
Button: This is the best spot to play in Texas Hold'em, so if nobody raises before us we can really play with a wide range of hands: all Aces, suited and off-suited, all strong and middle Kings and Queens (K-7+, Q-8+), all pairs, suited connectors (5-6+) and some speculative suited hands (10-8, J-9). Even a tight player must consider opening not less than 25%-30% from the button.
Small blind: The small blind is one of the most difficult positions to play. Our range here will be really tight and we must consider to 3-bet some hands when facing a raise from late positions. The advice is to play just with strong hands and 3-bet the top part of the range (A-K+, J-J+).
Big Blind: From the big blind, ranges are pretty similar to the small blind, except when there's not much action before us. To understand when defending the big blind is opportune, we always have to calculate pot odds. With an average stack and an opening from the button we can defend above 40% of the range, but just if we feel confident playing out of position with a certain type of player. 

Loose Players

There are many different kinds of loose players rather than tight ones: from loose-aggressive to loose-passive (the so-called calling-stations), including maniacs (who play every single hand and never fold to a bet) , "spewers" (not afraid to gamble a spot) and so on. Here we'll consider just a balanced aggressive player, who has a good knowledge of all dynamics and knows how to play post-flop.
The number of hands we are going to be involved waves from 15% to 40%. From early positions we can either play strong hands or suited connectors, broadways and speculative hands. We can also include a 3-bet/ fold and 4-bet/fold range, depending on the information we have on the others.
Early positions: A loose player can consider opening almost all suited Aces and most of the off-suited ones (A-9+), all broadways, suited connectors (7-8s +), pairs (5-5+) and some speculative hands (Q-Ts +). A wider range than this one requires a big stack and a lot of confidence in the post-flop game.
Middle positions: The range from middle positions should be pretty similar to the previous. In this case, we can include all pairs, some more off-suited combinations and some more connectors (5-6+) or speculative hands (T-8+).
Late positions: Aggressive players might open from late positions with any kind of hands, but this cannot always be a profitable choice. A more reasonable selection of starting hands should include all middle and weak suited Kings (K-6s+) and Queens (Q-6s+), some more speculative hands (J-7s+), off-suited connectors (7-6+) and weak suited connectors (4-3+).
Button: Here we are. From this position loose players can really open above 70% of their range: apart from all hands mentioned before, we can add all suited and off-suited connectors, one-gap, speculative hands and, in general, all face cards. We always have to be careful when we play against one of them though: the fact that a loose player is going to use a wide part of the range doesn't mean they never have strong hands. A lot of players make terrible mistakes underestimating the real strength  of opponents' hands.
Small Blind: Although small blind range should be pretty tight even for loose players, we might feel confident enough to 3-bet or 4-bet with a certain kind of hands, in order to steal or simply because we really do have a premium hand. Therefore, a balanced 3-bet range must include both monster and weak hands with a good post-flop equity, like suited connectors or some kind of suited broadways. Using just the strongest or the weakest part will make us exploitable, that's why we need to mix things in the best way possible.
Big Blind: Nothing can discourage a loose player from defending the big blind. With just one or two players involved in the pot, we can call or re-raise with more than 50% of the entire range. In this case, the largeness of our defense range can be exploitable from tight players when we both hit a top pair. So, knowing when to give up is really important at this stage: that's what makes a difference between a strong loose player and gambler.

Facing a 3-bet

Facing a re-raise is always complicated as long as we don't have Aces or Kings. To know when to call, re-raise or lay-down our hand, we need to have a clue about our opponents. As we have seen before, tight players do not have a wide 3-bet/fold range and sometimes they just don't have it at all. With all premium hands could be really profitable to re-raise a tight player and just flat against a loose one. The reason behind this choice is really simple: trapping a loose player means facing a varied range of hands which might be crushed from the one we have been dealt.
Tight players usually 3-bet from 2% to 4% of their range, while loose players can easily reach out 8% or more. By doing that, they will be less readable as well as more exploitable in some particular spots, especially when they play out of position.  

Blind vs blind

Blind war is still one of the most difficult situations to handle for an amateur. When to raise from the small blind? When to flat or when to fold directly? These questions have not univocal answers: it always depends on our strategy and ability to play post flop. There are players who defend 100% of their range from the big blind while others tend to fold even too often as soon as they smell troubles. The range of hands we should play in blind war, whether being tight or loose, mostly depends on our ability in the heads-up game. A good tip is to acknowledge when the opponent is stronger than us and avoid to be involved in uncomfortable situations, which may lead losing the entire stack just because of a proud reaction. Poker is a war: to succeed it we don't necessarily have to win every single battle, but just the right ones!