for this purpose). If you're worried about something, create a plan for the next day of what you'll do to start addressing those concerns.

Generally, making sure you're getting enough exercise during the day helps. Also, having a regular sleep schedule.

If I'm really wired, sometimes I just get up and work until I start feeling sleepy. I figure if I'm going to be awake anyway, I might as well get a jump on the work I need to do the next day (especially knowing that I'm probably going to feel tired tomorrow).