One thing that I have been trying a lot recently when I purchase clothes, shoes, anything I wear, I will first and foremost try it on in the store. Although trying things on in the store is often times a pain in the butt, it will prevent you from buying a lot of things that are impractical or don't fit. Dressing appropriately is difficult to discover when you are looking at an item on a hanger. Its about body shape, color, fabric, fit, etc., and it will be impossible to see these things without trying on your own body. In addition, if the clothes don't fit, always always ALWAYS return them. Commonly, when I buy new pairs of shoes that end up giving me blisters, I just throw them in the closet and forget about them, which is basically like throwing money away. Barry Schwartz talks about in his book, The Paradox of Choice, that we will often hold on to things that we don't use until the "psychological value" has worn off. We feel this need to keep these items, because we spent money on them, but we don't use them. The main reason to try things on in the store is to prevent you from bringing an item home so that it won't end up in your closet for the rest of its life.
A common suggestion from the folks at What Not To Wear on TLC is to bring clothes that may need a more appropriate fitting to a tailor. And if it makes the difference between wearing or not wearing clothes, or even being more satisfied with how a piece of clothing fits, consider having the items alternated for your own body. We're all different and don't fit the designer's size!
When you shop for clothes, shop as smart as possible and make sure these clothes fit you personally! You will get more wear out of your clothes, and spend less on the ones you never wear!