A good spot to avoid c-betting is this: let's say you raise from MP with 77, get several callers, and see a flop like AQJ. C-betting here is just throwing chips away in most cases, when I'm in a situation like this I'm generally not putting another chip into the pot.
In dollar SnG's people tend to play fit or fold OTF more but in CC games, you do have a lot of players who will float you in position with ATC to see if you check the turn.
If you're c-betting a lot, don't check your flopped monsters (FH, nut flush) because that gives your hand away. This is absolutely the best place to c-bet the flop with your usual size bet and then you could bet small on the turn because it can make your hand look weak. Depending on the situation, this can look like you missed the flop and think the villain is floating, but you're trying pick up the pot cheap and at the same time be able to get away without too much loss if he raises you on the turn. However, if you flopped a straight and you think villain is drawing to a flush on the turn, then you had better not bet small and charge him to chase his draws instead.