Continuation Betting or more commonly known as "C-Betting" is a play where the pre-flop aggressor continues his aggression by betting on the flop. C-betting can achieve two things:
1) To get more value in the pot by betting when you think you have the better hand and hoping weaker ones will call.
2) As a bluff by betting when you missed the board and using fold equity to win the hand.
Knowing how much to C-Bet as well is very important. There is no need to risk a large C-Bet bluff when a smaller bet will have the same results. After estimating your opponents hand range, knowing when to use the C-Bet can drastically affect your win rate.
Example 1: You have AK in the CO and you raised to 4BB. Folds to the BB who calls to see the flop which comes:
The BB checks to you, the aggressor. Should you C-Bet? NO! Although we are the aggressor and the BB did check to us, the reasons for checking outweighs the reasons for betting. If we were to C-bet with the intention of taking down the pot here, it is likely we will get called as this flop is very wet and hits our Villains range pretty well. Much better if we save our money for a better situation and take the free card and hope to improve our hand.
Example 2: You have AQ in UTG+1 and raise to 4BB total. It gets folded to the Villain in the CO who calls while the button and both the small blind and the big blind folds. The flop runs out as follows:
It is you to act first. Should you C-Bet? YES! While our top pair, top kicker is likely to be the best hand here, the board is quite wet, open to a lot of draws. If we C-Bet, not only are we getting worse Queens and other pairs calling giving us value, we are charging other hands from draws that could break yours. How much should we bet? Since we have a good hand, we want value and also to protect our hand. A larger bet accomplishes both so somewhere in the region of two thirds to full pot. Also take note that we are out of position. Check raising may be a option but if our opponent chooses to check back and get a free card, it could end up costing us the hand. This is a good example of C-Betting for value/ hand protection.
Example 3: You somehow managed to get your way through to a live major tournament final table where it is now heads up. You are on the button/small blind and look down at 910. You raise up to 3BBs and the cretin on the big blind calls. The flop comes as follows:
Your opponent checks to you. Should you C-Bet? YES! The board is very dry, unlikely to have connected with his hand. A C-Bet from you takes down the pot a very large percentage of the time here. How much should we bet? Since it's likely he doesn't have anything, a smaller bet around one third to half the pot should do the trick. If you were to bet full pot instead, the times he does have something you are wasting extra money this way. So figuring out the correct bet size is an art in itself. But assuming you are actually heads up in a major tournament, unless your opponent is the world's luckiest player, he will very likely to be quite skilled and knows the C-Bet. So he will also understand that a very large percentage of the time, you will have also missed this flop. So we cannot just always fire out a C-Bet in this situation or else we run the risk of becoming predictable. But that is another lesson for another time.