I think a lot of it depends on the toughness of your opponents. If your opponent is loose and passive you can c-bet more often, but a smarter opponent is unlikely to give your c-bet much respect on an 8,6,3 board. I think board texture is also crucial, you really one one face card and two smaller cards. You should also sometimes just check the flop to add unpredictability, I think I use to have the same issue but I've tried just checking randomly to throw off my opponents.
A lot of opponents have become wise to the cbet and they'll try to float. This is where checking the turn sometimes becomes important and then the c/r when they try to steal (which they'll do often, if they don't then you can bet the river.)