I would approach this with two things in mind. 1. Pick something you can do in a relatively short time, say less than one year. That way you do not run out of

I would approach this with two things in mind. 1. Pick something you can do in a relatively short time, say less than one year. That way you do not run out of steam working on it. 2. Pick something that you will learn a new skill or skills working on. Regardless of if what you choose succeeds or fails, you still come out ahead with a new skill.