Everything in poker boils down to having the ability to read your opponents. Creating image, using image and psychology, positions, math, and so on, are all important ingredients of winning, but extracting the most with your winning hands and losing the least with your losing hands is the basic principle. To do this effectively, you must have the ability to read the strengths of your opponents' hands. Every pro I know or have ever spoken with always asserts that reading your opponents is the most important part of the game. I hear many people say that you cannot read hands online, that it's impossible. This, to me is absurd and I disagree.
I'll be talking about no-limit hold'em here, but you can apply many of the principles to limit games.
The argument of not being able to see your opponents' actions and reactions keeping you from knowing their strength is a poor one at best. Reading your opponents includes many things, only one of which is physical tells. So, it can be said that it is more difficult to read hands online than live because you are missing that one constituent, but certainly not impossible. The elements of reading hands are betting patterns, bet speed preflop and on the flop, turn, and river, bet amounts in relation to pot size and in relation to stack, betting position, and knowing an opponent's mindset based on his personality, chip count, and what has recently happened to him (his table image). I will give you questions to ask yourself such that, when you combine all the answers from all the elements, you will be quite accurate in determining if you are beat and in knowing how much you can extract from him when you are ahead.
The betting patterns of your opponent can tell you the likelihood of his holding a strong hand. Questions you should ask yourself are: What is the frequency of his raises? How much does he raise preflop? Does his position seem to matter? Is it more common for him to raise from some positions more than others? Does he always bet the flop? Does he always check when first to act? Is he an extractor or a "fear bettor"? Is he crafty or straightforward? And so on. Pay attention to consistencies and inconsistencies to determine where something looks fishy. From answers to these questions you can get a good read on the relative strength of his hand.
The speed of a person's bet is often a good indicator of types of hands he may hold. Oftentimes, a quick heavy raise preflop indicates a strong ace, whereas a slower heavy raise preflop is often a middle pocket pair. Of course, you need to combine all the elements to determine this. Know your players. Typically, fast bets preflop and on the flop exhibit strength and slow bets on the turn and river exhibit either weakness or a trap (slow play) with the nuts.
Questions to ask yourself are: How quickly does he fire out at a flop? Has he been betting quickly each time? Slowly? Mixing it up? Do his slow bets on the turn and river usually mean a trap or a bluff? The speed of a call or even a check can also be an indicator of holdings. Once you determine the level of craftiness of a player, you may, for example, find him clicking the check-in-turn button with the nuts so, as the action comes around to him, he will check immediately and it will look as if he had the fold/check-in-turn button clicked and people will pay him less attention. This is a tricky move online and we will discuss how to misrepresent and trick others online in later columns as well. A quick call often represents a strong draw to a straight, a flush, or both. So pay close attention to speed online but also realize that sometimes slow action can simply mean the player is away from his computer or in multiple games.
The amount of a player's bet is another element to notice when deciphering hand range or strength. Questions to ask are: How much does he bet in relation to the blinds? Is he betting an amount that says he doesn't want callers, and why? Is he trapping you by luring you in and giving you odds to call? Based on the personality you gave him by observing him, would he be afraid to play after the flop? Is he pot-committing himself with his bet? What value is he giving you to call in relation to what is already in the pot? Is he pricing you out and why? Does he vary his preflop bets and if so, with what reason, if any? After a flop with draws on it, is he putting in a small bet to slow you down? Overall, use common sense. What makes sense? What doesn't?
What position is he betting or calling from? The earlier the position, the more strength it represents. The later, the weaker. But many players can bet from any position with any hand, giving false tells. Pay attention to position and notice it but don't rely on it. Just use it as another element to include in your equation.
Last and very important, know your players! As, I will often tell you, you have to know what types of personalities you are playing against. Questions to ask are: Is he an aggressive player? Passive? How much ego does he have? Does this make him defensive of blinds? Does he steal from position? What has he typed in the chat box that gives you an indication of his personality? Does he chase draws? Does he get a thrill from bluffing or picking off bluffs? Is he desperate? Is he content? What does he think of you? Pay attention. Get into his head. Walk around in there and figure out his mindset. Remember also that a player holding the nuts often looks the same as weakness. Knowing your opponent's mindset and tendencies will help you determine which it is.
Once you have figured out how he thinks (and that is always changing, so pay attention) and you can answer all the questions, you will likely know right where you are at in the hand. Over time, these questions will come naturally for you and the answers will come quickly. So, question everything and analyze each situation and don't just play your cards. Play your opponents, know their strengths, their weaknesses, and their tendencies, and know your own image, because often their bets will be made solely because they think they can get you out. You need to recognize these as well. Make sure you are paying close attention when not in the hand. You will gain lots of information that you will need once you are involved. Reading your opponents while playing live is much the same. You just get the added bonus of being able to see their actions.
If you study any one aspect of the game, make reading your opponents the most important. It will pay off the most.
Focus and analyze.