Playing the game of poker is not just about playing the cards. In fact, the cards themselves are just something you use to play against your opponent. Most of the hands that are played in the big poker games do not come down to one lopsided hand versus the other. They come down to how one person out bets the other person and who suckered in what to play the hand.
The trick with poker is not only knowing what you have and your probabilities but also knowing what your opponent has. The first tactic you can start trying to practice is, guess (in your head of course) what the other person has in their hand and also watch how they played it. After a while you will catch yourself starting to actually get what they had in their hand and then be able to play off of them from there.
You can catch all sort of little "tells" that your opponent is giving away. The first thing I look for when I sit down at a table is the posture of the people I am sitting with. Are they leaving forward, kind of hunched over the table? If so it means that they are not confident in their playing ability or their hand. Are they leaving back on the chair with their chest sort of puffed out? Well that means they either have a good hand or they are confident that they are a better player then you.
If someone was not betting the whole night and then they start firing off bets like a gun-firing cowboy from the old west, then you need to be wary. These players tend to only play hands that are in the top 25% of winning hands and if you are getting into a matching match with this player then you know that they are going to play it down to the end. Do not limp in there no matter what because it is going to cost you to see the cards. Make sure you play these people smart.