Remember the performers. Remember the listeners. Stay in touch with both. Put yourself in their place. Think about the mechanics of musical communication.
Vital ideas come from experimentation with raw materials.
Re-visit basic elements to discover their pattern possibilities for yourself. Composition is, in short, an application of a composer's theories about music. Everything about you goes into your composition. As a self-critic, your primary goal is to identify what you are trying to accomplish as a composer. Once you establish this, criticism is a process of judging how effectively you achieved your goals.