Wearing a belt is something that you need to try out for yourself. Some of us have bodies that belt well, and some of us find it much harder to find a belt that is flattering. Here are some easy tips on how to wear a belt.
If you have a defined waist why not show it off. You should definitely belt away. If you have a long waist, wider belts work, if you have a shorter waist, go for narrower belts so they don not further shorten your torso. Further, if you have a short waist, think about color blending the belt, rather than contrasting the color of the belt. Of course the opposite applies for my long waisted ladies. You may find that it is easier to belt a longer garments, such as a dress or a long cardigan, than a shorter garment, if you have a shorter waist. This is because the length of the fabric creates a longer vertical line, so some breaking up is not so shortening, as the visual shortening of an already shorter garment.
Belt picture from http://www.polyvore.com.