The process for breaking up your range into categories is the same for making a flop C-bet as it is for any other type of bet, so this answer ought to have a wider benefit than merely helping with C-bets.
Categories and Frequencies - get to grips with these and you will find it easier to break up your range.
Now before GTO came into force, I used to focus mainly on categories. I used to consider my hand strength, the board texture, my villain etc and I would come up with a solution that would be the same for all similar situations. So, if I flopped top pair against a passive opponent, I would C-bet always, without considering frequencies.
To be honest, I still do this quite a lot and for the most part it doesn’t matter, but I am learning to take into consideration frequencies, especially against stronger opponents or against opponents with whom I play regularly.
The problem with always taking the same action (e.g. C-betting top pair) is that you become predictable and readable and this hands a big advantage over to your thinking opponent. There is also the added problem that you can easily become unbalanced in your overall strategy. A lot of players will bet when they are strong and check when they are weak. This is going to allow your opponent to make very accurate decisions, when the aim is to make your opponent make mistakes.
To make your opponent make mistakes, you need to be C-betting with a mixture of very strong, strong, mid-strength, weak and very weak hands. Then you need to think about how you are going to weight your frequencies for betting within each category.
Overall, you are looking to have a C-bet frequency of around 70%. If you C-bet more than half the pot, this could be a bit lower and if you C-bet less than half the pot, this could be a bit higher. You can then look to adjust for your opponents. Add more bluffing hands in against those who fold too much and add more value hands in against those who call too much.
Let’s consider the categories:
1: Very strong made hands - here, board texture will play a huge role in how likely you should be to C-bet. If you hold KQ on a AJT board, you are likely to get action and can consider C-betting some of the time. If you hold TT on a TT3 board, you are very unlikely to get action and should check almost always. This category will have an overall C-bet frequency that is quite low. These are ideal hands to trap with and by doing so, you gain natural balance to your range. They make up a very small, but significant part of your range. You should always be mindful of how you would play a “nut” hand. If you take the same betting line but wind up with nothing at all, you have a credible bluffing spot, whereas if you take a different line, you might find it hard to represent a very strong hand.
2: Sets, Trips & Two Pairs - these are going to play very similarly to made hands, except that in really deep spots, you should be aware of how likely it is for an opponent to either hold a stronger hand or make a stronger hand at showdown. In practice, I usually combine categories 1 & 2 and only mentally separate them when an opponent starts playing back at me.
3: Overpairs - any one pair hand is vulnerable in deep-stacked spots. Pay attention to the SPR (stack to pot ratio) at the flop stage. If the SPR is less than 4, you are frequently going to feel committed to your overpair and there is less sense in keeping the pot smaller. In these spots, you can quite often C-bet a very high frequency. Board texture, range advantage and nut advantage all play a role. Very often you need a mixed strategy of sometimes C-betting and sometimes checking. When this is the case tend to C-bet with your strongest overpairs and check with your weaker ones. If the board is dry, choose a smaller bet size; if the board is wet, choose a slightly larger sizing. You should normally be value-betting either immediately or on the turn, but watch out for skilled opponents with a nut advantage, capable of bluffing you off your one pair hand.
4: Top Pair - much of what is true of overpairs is also true for top pair hands. If the SPR is less than 3, it’s often hard to justify folding, so as long as you have value, you can C-bet a really high frequency. In higher SPR spots, you want to have some balance in your strategy. I like C-betting with top pair top kicker 100% of the time, but mixing things up with weaker kickers. It’s often very useful to have some of these hands in your checking range.
5: Weaker Pairs - pairs below top pair are often great candidates for checking. You can check out my video series on how to play middle pair here. You do need to C-bet with them sometimes though. If both players have wide ranges or if the board is dry, a weak pair can be a good value betting situation. If you have a piece of a draw as well as your pair, that might be a good reason for C-betting too. If your C-betting range doesn’t have enough hands in it, you need to come up with combinations to add to the range and weaker pairs are sometimes good candidates, though I usually look to my drawing hands first.
6: Strong Draws - these are usually excellent hands to C-bet with, especially if you are drawing to a nut hand. Always think about your overall C-betting frequency and try ensure you are not betting too often or not enough. There will be times where you don’t need too many drawing hands in your C-betting range and times when you want most or all of the drawing hands in it. Adjust for your opponent after you’ve considered your optimal range. Often you’re going to want to include more of these hands against opponents who overfold either immediately or on later streets.
7: Weak Draws - you need to be aware of your odds and outs. Some weak draws are obviously better than others, so you need to be cautious of C-betting too often with very weak and vulnerable holdings. If you have a pair as well or a combo draw, that certainly makes C-betting more attractive. A lot of the time your choice is going to come down to how often you think you can make your opponent(s) fold. Otherwise I would be less inclined to bloat pots with weak draws.
8: Two Overcards - again you need to think about your equity and do some range vs range analysis. Holding two overcards can be much stronger than it looks. If you have a draw as well, even just a backdoor draw, think about whether it is a nut draw or a weak draw. Both probably justify a C-bet, but certainly the strong backdoor draws, such as an ace high flush draw, needing two more. You definitely want to be C-betting with 2 overcards a good percentage of the time, as it is one of the strongest types of hands you have ih your “missed flop” batch of hands. Look at the board texture and consider your entire range.
9: Ace High - interestingly these are some of the hands that players fail to C-bet as frequently as they ought to. By doing study in a range tool such as Flopzilla, you will see that ace high is sometimes quite a reasonable holding, especially in a headsup pot. If you think about all of the hands in your range where you missed the flop, you need a decent percentage in your C-betting range and ace high hands can be great candidates, especially on dry boards where it is hard to find 70% of your hands to C-bet. That said, you want your opponent to be calling with worse or folding better hands. When neither of these are likely, you are better off checking.
10: Air - most of your junk you can check with, but once again consider your entire range and think about C-betting some air some of the time. Consider which hands have some backdoor potential. You want to be continuing to the turn with enough weak hands to give your range balance. On really dry boards you are going to need to grab a chunk of these hands and get brave with them. Most players do too much checking and folding with their air, at least on some types of flop. Against calling stations, though, don’t even think about it!
Do yourself a favour and spend some time with Flopzilla!
Happy C-betting :-)