I've been very lucky with my betas. It's great to be able to hand over a fic that you know has a major problem and have them be like "Dude, NO" or "Fix this, dumbass." Except nicer, lol. And then the lightbulb goes on and you feel relieved because someone can see the problem and fix it.

Years ago when I was first starting out writing fanfiction for other fandoms, I made a pair of friends who were not only fantastic writers in their own right, but were also professional editors in real life. They really, really helped me get a feel for what was important to cut by taking a red pen to my stuff and just tearing it to pieces. But still, having a second pair of eyes is fantastic, although I don't do that for everything that I write (although perhaps I should).