Pick an event in the future (2-3 months) in which you REALLY want to look good for. Now everytime you work out, think of that event and how good you'll look. Great motivation!
Mines my first day of school at this new school I'm going to. I want it to be the START of the new me, the skinnier, healthier me. And I am SO excited for it. Even if I'm not at my goal weight, I know I'll be healthier!