Evaluating board texture is key to successful continuation betting.
There are a lot of factors to consider when deciding when to c-bet on a flop. Among the most important of these is the texture of the board. A flop of K♥7♠2♦ is much less likely to hit an opponent's range than K♥Q♥9♠ . The former is relatively dry and light, while the latter is wet and heavy. Remember why you're c-betting in poker in the first place: it's either to get a worse hand to call, or to get a better hand to fold. Factor your opponent's hand range in with the board texture, and then decide why you're considering c-betting. If you can't come up with a good answer, don't bet.
All-in for now...