This was my experience, as well (I'm sure it didn't hurt that I was paying my own tuition, too...not easy to slack-off when investing that kind of dough). But I HAD to keep a day planner and get everything done well in advance. I still have to plan my workouts, as well, or else I don't get them in or I lose motivation.
It helped that I was so busy in college with work and school that I didn't have time to waste. I do best when I am under the gun.