I found that writing prose until I run out of clarity and then switching to proof-of-concept code is even better. The constraint of making an ambitious design work with a minimal change-set is a nice way to work for a day or so.
Lots of features or fixes don’t require in-depth thinking to get started. But when they do, sorting out the ideas and tradeoffs in writing helps a lot.
Write until I run out of ideas, flesh those ideas out, write about the nuances I found. It’s a nice feedback loop!