The continuation bet or C-Bet is probably one of the most popular poker plays today. It is very important to understand C-Bet's for this reason, not necessarily so you can use them yourself, but so you can recognise them and play against them effectively.
A C-Bet is a bet that is made on the flop, by the pre-flop raiser.
The pre-flop raiser is continuing to show strength and build momentum by betting the flop. If you happen to play against an opponent who doesn't appreciate the value of a c-bet you will find it to be incredibly valuable. Opponents will struggle to call the c-bet if they've not made a pair, draw or better on the flop. The bettor is showing incredible strength and it's common that inexperienced players will fold to these bets around 2/3rds of the time. This is due to the fact that your opponent will only make a hand on the flop roughly only 1/3 of the time.
On the other hand, if you were to check on boards where your hand was not strong enough to bet, you are giving your opponent the chance to put you into a tough spot by betting, making an improved hand on future streets or taking the hand to showdown where you could be beaten.
Due to the fact you typically won't hold much when making a C-Bet it's important to get your opponent to fold for as cheap a price as possible. Sometimes you will get called and lose the C-Bet and your pre-flop raise. It's important to minimise this amount.
Why bet full pot when betting 1/2 pot will still provoke a fold?
Ultimately you want to find the perfect amount. Bet the lowest amount possible that will still deter your opponent from continuing in the hand. In situations where the hand has been 4-bet preflop it's possible to C-Bet for 1/3 of the pot and still take down the hand with nothing. It's all about minimising your risk.
A good player knows when to C-Bet.
7 8 9 is a flop with an incredible amount of potential. Your opponent could have any number of hands that he is simply not going to give up with. Two hearts for a flush draw, a Ten or Six for an open ended straight draw, easy pairs, sets and a lot more random combinations of the above. This is a good board to play with caution and maybe let your opponent take home.
A62 is a flop with very limited possibilities. There are no draws here and it's unlikely that the opponent called a preflop raise with a six or a deuce. In fact if the opponent is competent it would be rare for them to call preflop with an Ace as when a board like this comes they can get themselves into a lot of trouble if you have them outkicked, which isn't unimaginable if you're showing strength as a preflop raiser. Regardless, big Ace's make up an extremely small part of their possible holding as they will typically re-raise these. Bet 1/2 pot in this situation and your opponent will fold the majority of the time.
If you want your C-Bets to be an effective tool in your arsenal it's very important not to over use them. Opponents will begin to fight back. If you feel your opponent could have a hand in a particular spot and it is going to be beneficial for them to see you not C-Bet a particular hand, just give up and live to fight another day. At lower stakes it's probably a bad idea to get into huge bluffing wars where there is just so much easier, variance free money to be made in other spots.
When you hit a pair or a big hand on the flop you will probably want to bet. It's important to not let your bet sizing tell a story and to balance your ranges. Sometimes when you have nothing you will C-Bet 1/2 pot, so sometimes when you have a strong holding you should also C-Bet 1/2 pot. Of course the aim is to bet larger amounts when you have a strong hand, especially if there are draws on the board, but the name of the game is to make sure your opponents do not notice any patterns.
At low stakes the concepts mentioned above will work, but a more profitable application of the above strategy is to look for regular players, who are competent and take poker seriously and exploit them when they're employing the above strategies. For example when your opponent C-Bets a dry board (Like the one shown above) you can either put in a modest sized raise or call the flop (if in position) and force action on the turn. Both of these adjustments should be profitable if you have correctly defined your opponents.