Theme and variations. Pick something, doesn’t matter what it is so long as you care about it (feel it tug at your heart or your curiosity — I prefer curiosity but some people are emotional).
Make one you like (this could take a while, enjoy the ride).
Make the next one either bigger or smaller, in a different medium; redo the oil painting into a watercolor; remake the color version as a monochrome; turns the masses into lines; change the format from a rectangle into a square, et cetera.
Play it in every key signature.
[This post is dedicated to the life and memory of Paul Squires of Gingatao, a great poet of the early 21st century.]