I admit it. I've been struggling with perfectionism pretty much my whole life. (You'll have to ask my mom how much of it manifested when I was a two-year-old, I guess.) There's a particular aspect of it that sticks with me. If I couldn't do something perfectly, I'd rather not do it at all.
No settling for "okay." No such thing as "good enough." All or nothing, a hundred percent or zero.
If I were still full-throttle in that zone and trying to write novels, I think I'd be dead already.
Don't get me wrong. Striving for excellence is great. It's something we should do, and something I still do. But writing is never going to be perfect, and it's going to be very unperfect for a long time before we get it as close to perfect as we can. If we lock onto the flaws during the process, we're never going to move forward. So here's what we can do:
We can let our first draft suck.
It's okay. We have permission. It's allowed.
If we're coming up on a fight scene, and we know we have a hard time with action descriptions? That's okay. Write it badly. Let the words come, because then we have something to work with.
I'm not saying editing/revising as you go isn't allowed. Personally, I tend to do that as I draft. Others, like Mindy McGinnis, prefer the first draft to be "word vomit"—just get it all out there and tidy it up on the first revision pass. When I feel my perfectionism creeping up, though ... when I get those doubts saying I can't write what I need to well enough, so I may as well not bother at all ... that's when I know I need to just let it spill.
Once it's out there, I can see how bad it really is. Maybe it's worse than I thought, and I need to educate myself on how to fix it. More often than not, though, it's not nearly as bad as I expect.
For me, the fear of sucking is much worse than actually giving something a shot. So I'm trying not to fear it. I'm trying to embrace that suckiness, knowing at worst, it'll only be temporary.
A crappy scene can be revised and fixed. A blank page is just a blank page. Great for origami. Not so great for telling a story.