I use a calendar to keep track of my daily music practice, similar to the Seinfeld productivity method (http://lifehacker.com/281626/jerry-seinfelds-productivity-secret). This has been extremely helpful, as I practice every single day, even when I go out of town (having a Traveler brand guitar has also helped here). When I first started playing, I did not do this, and it showed.
For those of you who are/know/have music students, do they find practice journals useful? I'm wondering if it would be helpful to keep track of more details on what I am practicing (songs, scales, techniques), or if I should just shut up and play/practice.