My idea is to work on small toy things I can finish in uhh 30 minutes, a day, a week, 30 years etc Ponder the big problems in life, read up what was done to progress the progress sufficiently to be able to participate in attempting to solve the puzzle. Look where others didn't look. Eventually you find a problem that fits your ability. This could be a small problem that takes 5 years to complete or a big problem that takes 1 day once you know how to do it.

Sometimes you just have to try stuff. Without going into details my 2 most stupid ideas turned out to be completely hilarious and unlike anything one could imagine in advance.

Enjoy the process not the results.