You improve your models of how things work and come up with epiphanies/ideas by taking action and practicing.
Don't wait until you have the perfect startup idea, or have figured out all the answers on how to write well, or have learned all the theory.
Taking action and making things without perfectly seeing the whole picture is uncomfortable, but this is the best way to tweak and improve your model.
Draw your map as your journey towards your goal, not before you get out of the house.