My brother is the Tuba chair with the Winnipeg Symphony. His rule is pure simplicity: "Pick up the instrument very day." Of course he devotes a lot of time to practicing, studying, he drives hundreds of miles to take master classes from expert teachers.

But underlying it all... Pick up the instrument every day. I think Paul Graham made a similar point about startups failing: That success was built on the foundation of not dying, of not stopping. It's far better to have an organized plan, to use Pivotal Tracker, to have a clearly articulated question you are trying to answer...

But if you do something every day, at least you won't come to a complete halt. So do something, no matter how small, every day.