I'm a big fan of defining a structure for yourself, and then working to create something within that structure.
Over the years I've experimented with different versions of 52 Weeks challenges. The basic idea is that you give yourself the goal to create one new 'thing' ever week for 52 weeks. The thing can be a drawing, it can be a sculpture. It can be an essay, it can be a piece of music. Basically as long as its something concrete that you've made that you can share with the world it counts as a 'thing'. The goal is not to make perfect things, but to practice putting things out into the world on a consistent basis.
This is some of the music that I wrote for one of my first 52 Things challenges.