If you've ever been disillusioned at by trying to document what you did during 15 minute blocks on a spreadsheet - I'm really sorry someone ever suggested you "track your time."

It's a colossal waste of time. Do this instead:

Document when you switch from one task to another task. Do this for 2-3 days and you'll be AMAZED at how much more productive you are. But even better, you'll have incredible clarity on how much time you spent making it rain vs. spinning your wheels.