Cbetting oop will usually be profitable w/ 1-2 players on a lot of flops, because if everyone missed then the pot will often go to the first person to show aggro. My second barrels have been losing me money lately, so I think those should really be reserved for situations where you've got a good read.

That being said, there is nothing wrong with checking on the flop and if it checks through making your cbet on the turn. This has been pretty effective for me lately.