Having the right determination in your mindset is very important. Rely on your Coach for support, and if you don't have a helpful coach, find one. There are plenty of us out there that WILL help, so take the time to find the right one for you. Having the right coach can make the difference for you.
Second, join a motivation thread. Being able to discuss your struggles and successes with others goes a long way to keeping you on track.
Look for positives. Read motivating things daily. Set a plan for rewarding yourself with something if you can get to "X" goal - I don't mean an all you can eat buffet

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By the time you start getting to those goals, they will be reward enough though! When you start seeing good results you will get the kind of positive reinforcement you need to keep doing it.