It's weird, when I was first losing weight at home I also got this guy into doing it as well. He seemed to be the one who helped kept me motivated because the next day at work we'd discuss the workouts we'd done etc...
I moved back out across the country and lately it has been hard trying to find that motivation, until again him and I kept in touch and we discussed doing the P90X fitness program together. Well tuesday I wanted to slack, and of course he wrote on my wall saying he had just finished his workout and BAM motivation hit me to get off my mcdonalds eatting *** that day and to do a workout.
I think for me, though I've made rewards for myself at the end of the month if I complete the task I have going on, it helps me if someone else (Who I know personally who is struggling with the same problem and trying to accomplish the sort of same goals). I didn't choose for it to be this way, it just seems to work well for me
Also, I'm not very stricked on my diet, counting calories and going through the motion of what other people do I can't do. I find it exhausts me and I want to give up. So I go with the flow and I seem to be doing well (minus the holidays). If you feel the need to eat junk food, have a 1 day a week thing where you can eat that crap. Find meals you enjoy so it doesn't feel like a hassle to be doing this. Or if you want to eat a slice of pizza for lunch do it, but eat a healthier breakfast and a healthier dinner. You know? I don't know it works for me and I excersis and I'm loosing the weight by not just eatting rabbit food or following a specific diet.