Write down your specific goals

"Lose some weight" and "get skinnier" aren't smart goals – they're vague ideas that are unlikely to get you what you want. Instead, figure out what you really want to achieve. Is it a certain number of pounds? To fit that "skinny" pair of jeans that's been hanging in your closet for the past five years? Or maybe weight loss is just a side-effect of your health goals: to be fit enough to run after your kids without getting winded, or to clean up your diet to prevent or treat diseases such as diabetes.

Whether your goals are small or large depends on the kind of person you are – do you function best working toward grand plans or do you prefer to be able to check things off weekly? Either way, choose your goals, write them down – a note on the fridge or a secret file on your computer, it's up to you – and commit to achieving them.