Continuation Bets

I have been playing 25PL for a couple of months now, and trying to learn as much as possible from this forum.

One problem I have noticed is with continuation bets. At the tables I play, these are definitely profitable - I can take down a lot of pots on the flop. The problem I have is when one (or more)people flat call. Then I am lost. Do I check/fold the turn, bet 1/2 pot and fold to a raise?

I know it is highly situational, but I am looking for the things that I should be thinking about when I make this decision.

Thanks heaps.