Make time for whatever it is you're creating. I usually just go, okay i'm going to just be in my zone for the next ten minutes and that makes for a great starter. Sometimes it's a sound i hear like a busy station or the sound of raindrops on marble. I also admire that music can be more than just sound like John Cage said "It doesn't have to mean anything" but then there's a part of me that cares what chord progression i'm going to play and how that's gonna work with the drums to the point where I have learned to take time to think about what this music means and what it will mean to the listener. If you really care about whatever it is you're working on then learn to forget everything else and work on music for the next ten minutes or so on. Those ten minutes will matter. Trust.