Get some fitness help

Work with a trainer or coach. Workouts seem easier and are more effective with a professional prodding you along, plus you are a lot more likely to show up when you feel obligated ( especially when they are going to charge you anyway) When someone is watching you and keeping an eye on your progress it is more likely that you will do more and push harder. If you can't afford a trainer for every workout, try it at least once every week or two. The trainer can take you through a workout and help you to set goals for the next session.
If you don't want or can't afford a trainer, find yourself a good training partner. An ideal training partner will be someone who is at least as motivated as you are, preferably more. You will need someone that will show up. It is best to get a partner that is more knowledgeable about fitness and nutrition and preferably a little stronger.