Mostly, I read...with my grand total of 3 fics thus far (and my lack of anything resembling confidence in my own writing) I don't have a beta, though I do beta for others. I tend to be a perfectionist with my own work (in all respects of my artistic endeavors) which I think has saved what I have written from the most common "new fic-writer" disasters...

When I beta, I try to say what was good about the fic, not just what's wrong with it. I think it helps make the corrections more palatable and also encorages the strengths in the author's writing.