Planning my day is the most important thing I do.

I do what I call my "8 for the Day" which is just a simple list of the 8 things I want to accomplish. I always make 6 work tasks, 2 personal tasks, on Saturdays I flip that ratio and on Sundays there are no to do's.

I figure if I can't get 8 things done in an 8 hour day then I'm not spending my time effectively. It also helps you sit down and physically write what is important to you.