Generally, I would try to reach the showdown cheaply. It's a common WA/WB situation, you can't figure out where you are most of time. So try to lose less if you are behind. If you are ahead you will win at the showdown anyway, but it's usually hard to get value from a weaker hand in such situation. If I was a preflop raiser with KK out of position, and the flop comes let's say A37, I most likely would not c-bet there. Instead of this, I would check/call letting my opponent make bluffs sometimes. I could check/call one or two streets depending on my opponent. But no matter what I would try not to move my entire stack in the middle with this pair. If I'm in position on a A-high flop I would not bet too, I would check behind. Intsead of betting flop, I will try to bet on the turn if my opponent checks again.
Of cause, if there're any draws on the board, betting could be nice too. You need to defend your hand from a draw and you more likely will get paid from worse hands (generally draw hands).