Here’s a good tip from Advice to Writers on the importance of not getting stuck.
When you’re writing and come to a rough spot and the ideas just aren’t flowing, put down dummy text and keep on moving—especially if it’s at the end of the day and you’re going to stop. Your brain will never stop for the day, even if you have stopped working, and there’s a very good chance you’ll come up with something better. Also, at the very least, you’ll have something to come back to the next day, instead of a blank page. That’s important. ~Larry Gelbart
I do this all the time when I’m writing, whether it’s a blog post, a research paper, or even an email. Don’t get stuck. If I’m not sure what I want to do with a paragraph/section, I’ll just make a couple of comments about what I think that section needs to be about, and then I’ll move on. Normally, by the time I make it back, I have a pretty good idea of what needs to happen.