It seems to me that playing poker is essentially not doing stupid things.

that seems to be a good goal in general.

That said for now my goal is to win 50 percent of the pots that I bet on. 70 percent of the flops I bet on. 95 percent of the rivers I bet on.

playing for free is different because there is not as much to lose. Even in free tournements people don't enter them to lose. The ones that don't care so much, they are tired, a phone call comes, whatever, are quickly eliminated and play starts in earnest. The key at first is not to do anything stupid, somebody that is betting on a hand that could beat yours has that hand... except when they don't... :)