Refining a few of Ex's points above, and adding some related to avoiding a bad burnout:
1) Understand your season, particular to you and the area you live. Schedule yourself to be fast when it counts, and actually rest when it doesn't. Understand the principles of base and build.
2) Switch up training just for the hell of it. Do specific types of intervals in 4-6 week blocks, then do something new. Throw in plenty of group riding.
3) Skip almost any race you don't feel like doing, unless it's just raining or something. In that case, HTFU.
4) Maintain your normal diet as much as possible during periods of rest. In the past, I've let myself go during rest weeks, eating crap the entire time. It made me feel like crap, and I didn't want to start riding again. Taking care of yourself during periods of recovery (mental and physical) is important.
5) When life gets in the way, reconcile it and move on.
I'm a poster boy for #5 this year. Working full time this summer means I can't train like a pro, so I'm not racing like one. It's taken me a few weeks to reconcile that fact.