I've been learning a tremendous amount recently by painting these watercolor scenes. For me, I've learned that I need to use big brushes, squint a lot and stand back from the picture a lot. For the brushes, I don't mean to use something insanely big, but larger than I normally use.
This works for me because I tend to over emphasis smaller details, when I should be more focused on the larger picture. The details also don't matter unless the larger composition is correct. It's an endless search for balance between the larger picture and the details; neither one is more important than the other, but I am focusing more on the larger picture for now.