Here’s a little practice I do. Before I take a break, or before I finish for the day, I like to leave code broken. As in, cannot compile. And with a note indicating what needs to be done next. This makes it easy to get into coding mode when you start again, because you have a direct goal instead of having to do a big planning session in your head.
The idea came from Richard Gabriel’s “Patterns of Software”, where he explains he always leaves his writing in the middle of a paragraph. I’ve done that quite often too, since reading that.