If someone demonstrates skill or craftsmanship (ie, drawing), some good compliments are: praising the quality of the work ("I love the linework here"), praising the person for the skills they've developed ("wow that's so cool!").
Some bad compliments are: putting yourself down ("I could never do this"), othering the person ("people who can do this must have a different special kind of brain"), attributing their skill to something innate/unearned ("you're so talented, I'm jealous")