I have lost 5 lbs, need to lose 15 more. how to get into the right mind set is the big problem. Any suggestions?

HI! I find the best wat to motivate myself is to get out and do some exercise, watch the calories clock up on the machines. I always want to eat heaps of chocolate afterwards but am trying to eat fruit instead. My weakness will be starting back at work next week all the break time snacks around the place. I've got 16 pounds ish to lose so keep me posted as to how you go I want to know !!