Got a big project you need to get done? Tell someone about it. Web Worker Daily has more:
Commit yourself to someone. If you don't tell anyone that you're going to finish this project all at once, it's too easy to let yourself slide. You have to commit to someone ... your boss, a colleague, a client, someone. Tell them you're going to finish it all at once, and when you'll be done. Then email them the completed project (or call them, or whatever). Be accountable, and it will motivate you to finish.
This can apply to work or personal stuff; for example, you can get ready for a marathon by working out with a buddy. How do you hold yourself accountable? Please share in the comments.