You should try writing out of order
This is a really short post, because it's a really short and simple lesson. This weekend I did something I've always heard / known was okay, but never really believed made sense and therefore never really tried.
I wrote a chapter out of order from the rest of my work in progress.
*Gasp!*
That's right, I skipped ahead a whole scene. After writing "A," I couldn't think of how I wanted get to "B," so I just went ahead and wrote it and figured I'd come back and edit in a segue later.
I'd been stuck on this part of the book for more than a week, but then, lo and behold, I was unstuck. And, amazingly, once I'd written scene B, writing the intermediate scene to bridge between A and B was a lot easier, because I knew exactly where I was going.
Now chances are, you learned this lesson a long time ago. In that case, please go ahead and have a chuckle at my expense, it's certainly deserved :)
But in case you're like me and have always felt you needed to write scenes in chronological order, let me encourage you to try breaking that mold, just to see how it works. You just might find it unblocks places you've been stuck, and helps move your book forward.