Truly great ideas stick. You don’t have to document them because they make such a profound impact on you that they stay in your head.
Throw ideas at the wall and see what sticks. The ones that do are the ideas you should focus on seeing through. Remember that you might end up throwing some of these great ideas away. Doing good work doesn’t come from your ability to create genius from thin air—it comes from having the discernment to know your end goal and try different ideas to bring it to life.