There is a great deal of truth to the old adage of allowing yourself to write a crappy first draft. Anne Lamont has touted this method for years. Other, similar advice urges you to just get it down and go back and fix it later. Steven Pressfield has an amazing blog post called "Cover the Canvas" where he espouses this very thing.
Here's an excerpt from that post:
"Here’s my mantra for first drafts. Cover the canvas.
What that means is get something done from A to Z, no matter how imperfect. A first draft doesn’t have to be great; it doesn’t have to be pretty. It can have gaping holes; it can leave every “t” uncrossed and every “i” undotted. Momentum is everything in a first draft. Get it done. Cover the canvas."
Yesterday I struggled to get through a chapter of my novel. I didn't have all the specifics worked out yet, and it kept me from getting any writing done. In essence, I was strangling my momentum. But I realized that if I just wrote the words, "Figure this out later", I could keep writing. And write I did. I finished the chapter, one I'd been working on for too long, and was finally able to move the story forward.
It's something I've had to learn the hard way. There have been too many times when I've let myself stagnate on a particular scene because I don't have it all figured out yet. That just creates a snowball effect. When I get stuck on a scene, I stray from the manuscript, which leads to procrastination, which leads to not writing.
I have a feeling I will have to remind myself of this very advice in the future. Maybe I need to put a sticky note on my laptop, one that simply says, "Cover the canvas." or maybe, "Keep moving." Either one should do the trick.