If you are trying to improve your diet, there's one big thing you can do that will change everything without you even changing your shopping habits - throw that microwave in the trash.
The fact is, a microwave operates under nuclear principles. The structure of the food you're eating is changed at an alarming rate as it cooks. Although it hasn't been proven this isn't good for us, it hasn't been proven that it's fine, either. Plus, the micro makes it too easy to overcook veggies, removing necessary nutrients.
So, if you're looking for a big change, at least start with storing it in a closet. You'll probably be surprised at how little you miss it.