In general: I don't praise them when they get an A on a test..likewise I don't criticize them if they get a C on a test. Instead I try to direct my admiration for their effort. When they worked hard to get the A, I praise the effort they put into it. Likewise, if they get a C, and we both know its because they didn't study, I criticize that. If however I know they studied and still got a C, I will still praise the sincere effort.

The basic goal is tie approval to "hardworking / perseverance" and not focus on specific outcomes.