You get the world famous "it depends."

Are you playing limit or NL? What is your position? What is your hand? How hard have you hit the flop, if at all? What was the action like pre-flop? How many opponents are in the hand?

First, contrary to what some may say, your post-flop play is dictated by your pre-flop play. You still only want to see 18-25%. It is your % win when flop is seen that matters.

Example 1. You hit a perfect flop! Ex. AA KK or high pair and you flop a set or a very low, unconnected rainbow board; flopped nut str8 w/ no flush; nut flush with no pairs on board...you get the picture.
The objective is to get the most money into pot by not scaring anyone out. Check up front. Slow play. Even give a free card to give someone a chance to catch something. This is the easiest example.

Example 2. You flop a Draw. Ex. Open ended straight or 4 to a flush. Are you drawing to the nuts or playing suited 23 free from BB? If there is not a lot of action semibluff. By semibluff I mean a 1/2 pot bet no little min bet. If your opponents are giving you a cheap card with a min raise call or even reraise to throw them off. It is also important to consider your pot odds and implied odds here.

Example 3. Top 2 Pair or TPTK. Be aggressive. Find out where you stand. Don't give a free card. The amount of aggression depends on the board and position. If you are in late position and facing a single bet, reraise to find out where you are at. If you are reraised again you might want to pause. Never just call. Bet or raise. If you are in late position and it is raised and reraised get out of the way.

Example 4. You miss the flop completely. Do you have overcards? How many 1 or 2? How many opponents? Are they tight? What is your position? If you are in late position and up against tight opponets try a bluff. But a bluff is not a tiny mini bet you gotta bet just like you do when you have something. Beware if the check raise! (Are you playing against rippy?...beware of the resteal). Only try a bluff when you have one or two opponents. It is also more effective if you showed strength pre-flop with a raise.

Your pre-flop play has a lot to do with post flop play because it can influence the number of players still in the hand and their initial read on your strength. If you see 40% of flops you will be playing too much of a guessing game post flop in a full game. Shorthanded is a whole different story where you play the betting and opponents and position more than the cards.