Generally, I'm pretty lax on the rules and line calling. As long as my opponent isn't cheating, I don't cheat. When my opponent cheats, I cheat back the exact amount of times my opponent clearly cheated.
It's not very honest on my part, but most of the time it gives them a wake-up call to say "I know you've been cheating, and I can do it, too."
I try to be as honest as possible otherwise. I tend to give up too many points so I don't go home with a guilty conscience.
I am an unpredictable player. Even I surprise myself with some of the shots I make.