I am a big fan of the check/flat call. If after the flop I am on a flush draw, I would probably check to opp. If he bets (depending on amount) I would usually flat call him, If I hit then a bet will follow. If he bets heavy after the flop, chances are he is trying to protect his hand against the flush. If this is the case I would check again if I made, and re raise his next bet......just me though.