Post-Flop Betting Introduction

Post-flop betting is all about controlling the tempo, keeping yourself in the position of power - that is, having your opponents deferring to you to make their decisions for them. Via your bets you can do several things.
You can use bets and raises to gather information about your opponents. One of the biggest mistakes a person can make is to check/call. I see player after player doing it and it is a fundamental error. Why is it wrong? Well because it is your bet or raise that defines your opponents hand. If you just check and call, then you really have no idea what your foe has. He could be on a draw. She could have middle pair. He could have the nuts. She could be on a stone cold bluff. Unless you bet, you just don't know. Betting and raising also has the additional benefit of letting you win the pot by causing your opponent to fold.
When you check and call, you not only eliminate that, but you also build up the size of the pot and make it correct for him/her to bet you out of the pot by applying pressure to you on the next street. There is also one additional benefit to betting/raising (especially when you have position) - if you are called, you will generally be checked to on the next street and if you yourself are drawing, you will be able to take a free card (or if you have a strong but not great hand, you can check and call a bet on the river, while you would not have been able to call a check raise on the turn).
Try it sometime. Say you flop middle pair out of the Big Blind against one player who limped in Middle Position. Bet it out. If you check, you know he's going to bet. What do you do then? Fold, call or raise? If you bet out, he'll either fold because the flop missed him (more times than not), call because he is drawing (either to two overcards he holds in his hand or a flush/straight draw) or raise because she believes she has the best hand. If you just check and call then you have no idea whether she has top pair or not. She could be holding nothing better than a pair of 2's but because you are checking and calling, you're eventually going to fold to her bets because of the uncertainty you have created (and generally speaking it would be correct for your foe to continue betting unless she knew you were the type of player who was a calling station).
You can put your opponent on a hand based upon their action/reaction to your bets and raises. Have you ever wondered how the pros can put someone on a hand? It certainly isn't because they are psychic. It's because they've seen something in the way a person is playing and/or betting or have seen the situation come up a hundred times before. That is where the experience you garner playing at Pokerstars or Full Tilt Poker in those low buy in tournaments is invaluable. The thousands of hands you play give you valuable information as to what type of hands a person might have or be playing.
To figure this out, you need to pay careful attention to how each player at the table plays. Do they bet strong with only strong hands, or mix it up? Do they bet weak when strong and strong when weak? What hands do they just call with? What hands do they raise with?
Watch and in time, you'll pick up on what they are doing. Are they just checking and calling when there is two of one suit on the flop? Probably a flush draw - make them pay for it.
Are they just checking and calling when there is two connected cards on the flop? Probably a straight draw - make them pay for it.
Did they bet small and call your raise with no potential draws on the board? Probably top pair bad kicker - make them pay for it.
Did they call your raise pre-flop and then check on the flop after you checked and then raise you on the turn? Probably slow playing something hoping to get more money from you.
Did they make an oversized bet into the pot? Probably a hand that doesn't want to get called and is trying to buy the pot.
Or how about that small but not oversized raise of your raise pre-flop? Probably wants a call because they have a big hand.
What about that oversized raise of your raise pre-flop? Well depending on the person, it's usually a hand like JJ/AK that feels like they have the best hand but doesn't really want to see a flop.
Betting will also allow you to build favorable pots for yourself that allow you to get paid off for your strong hands and can assist you in setting up future plays and moves. In the next part, I'll give you all an assignment to help you understand some post-flop betting concepts.