I'm a fan of early morning workouts because they make the rest of my day better. The problem is, once your alarm goes off, it's so easy to roll over, hit the snooze button, and skip out. You wouldn't be able to sleep in if you knew someone was counting on you to show up though, right?
So whatever time you like to workout, schedule a fitness date either with a friend, fellow runner, or a trainer. Knowing he or she will be there waiting and ready to go will make it impossible for you to miss it.