One tip I learned from Chow is to eat things that don't have a label. I know that all packaged food isn't bad, but a lot of it is processed, or synthetic versions of whole foods. Even a lot of packaged "healthy" has been altered in some way. If I can, I try and make the real deal at home or buy my food from the farmers market, bakery, or my local butcher. By skipping the label I'm getting more whole, healthy, natural food and less processed, chemically altered, unpronounceable stuff. I also cut back on a ton of packaging!
The next time you're out shopping see if you can cut back on labels, too — you'll find that you have a better idea of exactly what you're putting into your body.