These are some things that I like to keep in mind while composing. I would like to get feedback on them. What do you think of them? Do you think they are good to keep in mind? Do you think there are problems with them? Is there something else that you think is good to think about? (I know it's long. Sorry about that.)
There are three parts: big picture points, "small picture" (for lack of a better term) points, and creativity points.
The big picture points have mainly to do with structure. I think of a piece like a play with act I, act 2, and act 3. The first act introduces the mate