Hand reading is the ability to put your opponent on a likely range of cards. And even further, putting different likelyhood on different kind of cards within that range.
Sounds complicated? I am afraid it is. Especially since your opponents are doing their best to hide this information from you.
Nevertheless, if you want to become good at poker you really need to become good at hand reading.
Some players base their hand reading to a large extent on intuition and not that much on mathematical kind of analysis.
Personally I believe that some great players are able to do this with a high accuracy based on raw talent or lots and lots of practice.
For most "regular" guys though, I believe that to become good at hand reading you have to do a lot of thinking and practicing around it.
Think about it while you play, always try to put your opponents on hand ranges, and see how you are doing when you get a chance to see their cards.
Many beginners believe that hand reading is mostly based on keen observation of your opponents facial expressions, hand movements etc. at the poker table.
Most professionals do not seem to put that high weight on this though.
The knowledge about how a certain opponent or category of opponent usually plays and the reading of their betting patterns play a much larger part in hand reading.
The most common recommendation is to use information from a so called tell (a conclusion based on something other than betting patterns) when your judgement based on playing tendencies, betting patterns and odds makes it a close call.
The information below is focused on Texas Hold'em.
You can gain lots of information on the preflop play by noting if your opponents are tight (playing few hands) or loose (playing many hands).
Using analytical software like for example Pokertracker, Pokeroffice of Hold'em Manager can give you very precise information on how your opponents normally play.
At lower levels even some of the good players play quite mechanically, and are for example always opening with a raise when second to act and holding 77+ (pairs seven or better), AK or AQ.
You should also look for raising tendencies and what kind of hands your opponents are likely to call with.
An example on preflop opening raises as a percent of all possible poker hands is presented below. It is taken from full tables using a database with more than 5 million hands and over 40 000 players on this level and site.
It is based on averages for the 10 players winning most money at 1-2 $ no-limit at Full Tilt.
Most of these winning players are always opening with a raise (not merely calling) if no one has entered the pot yet.
UTG (first to act) 8 %
Second to act 8 %
Third to act 8 %
Fourth to act 10 %
Fifth to act 15 %
Hijack (two positions left of the dealer) 15 %
Cut-off (one position left of the dealer) 20 %
Button (dealer) 30 %
Small blind 50 %
So that is confusing? You have no idea what 10 % of the "best hands" means?
One way of learning is to use the different games and practices that are available on this site. If you do that a lot you will soon develop a feeling for this.
But if you think that is difficult I have developed a trick to simply calculate this by putting certain numbers of different kinds of cards and adding them together.
The formula I use give a very good approximation and makes it a lot easier to keep track of the value of starting hands. It is based on Sage, for those of you who are familiar with that.
The difference is that it is not based on "all-in against random hand".
Interested? Please write on the forum if you are, I would be happy to share it.