Enter everything you eat honestly and fully. Don't be afraid to see how many calories you ate or how many grams of fat there were when you make a not-great food choice. Many times, I'm pleasantly surprised to see that what I ate wasn't really that bad and that I'm still on track. Often one poor food choice isn't as devastating as you might think - and knowing you have been honest with yourself makes staying positive and on program much easier!
Tracking everything also makes it possible for you to make good choices in challenging situations, like restaurants or having dinner at someone else's house, because you have a better idea where the worst of the calories are hiding and what you can enjoy in moderation - guilt-free!