Find a gym buddy
A little help and extra motivation from a friend can go a long way. A few months ago, my friend wanted to get back into working out, so she joined my gym. I told her if she wanted someone to run alongside, however, she'd have to be up early with me. Reluctantly, she agreed to try my daunting AM sweat sessions -- now, she actually prefers getting her workout done early, and says that having someone there to swing kettlebells with makes skipping or slacking off less tempting.
A gym buddy can benefit the morning workout veteran, too. Now that my friend shows up to the gym expecting me to be there, it makes me want to prepare us a cardio circuit and design an ab routine that will keep us both engaged.
Can't find a friend who's up for the challenge? Try signing up for group fitness classes, whether it's spinning, Pilates, trapeze yoga, or CrossFit (for the daring). The group setting and designated class time that you have to show up for both act as extra motivation. Plus, what better place is there to find a new gym buddy than AT your gym? Everyone there is also crazy enough to get up before dawn to sweat, so you already have something in common.