Don't know your Armani from your Kmart casuals? Do you have to twist around and check the label to know what you're wearing? Time to brush up -- fashion illiteracy can stop your personal style quest dead in its tracks.
You don't need a degree in fashion to understand clothing. You just need to be more aware when you shop. Look at different fabrics. See how polyester feels compared to silk. Learn the difference between plaids and houndstooth prints. Figure out how to see differences in an outfit's stitching and cut.
Look for a variety of fabrics when you shop. Choose some cotton pieces for everyday, silk ones for dressing up, wool for the winter and linen for spring and summer. Learn how to care for your fabrics too: Cotton/polyester blends are great for everyday because they barely wrinkle, but you'll need to keep your linens carefully pressed if you don't want to walk around looking rumpled. Silks are more delicate, so be extra careful about spills.
Know which fabrics and textures are most flattering. Shiny, bulky, or stiff textures can make you appear bigger than you really are. Smooth, matte surfaces, like cashmere and jersey, can really slim you down.
As a student of fashion, your "textbooks" should be the big magazines, like Vogue, Marie Claire and Elle. Study the ads and articles, including the picture captions, to see what fabrics and colors are "in" this season. Look to the masters -- Dior, Dolce & Gabbana and the like -- to see what elements they use in their designs. Use those designs as inspiration to create your own fashionable looks more affordably.