One thing I used to do, ten years ago, was fill sketch pages every morning. Two or more 11x14 sheets. It's a danger to let such a thing eat up your time. It can become a method of avoiding the real work you're too afraid of screwing up.
But when I look back on them, those sketch sheets aren't bad. And it's hard to argue that it had no positive affect on my other work at the time.
Maybe that's something I should do again...