Jewelry is a balancing act.  It’s all about size, scale, and proportion.  If you’re wearing huge earrings, skip the necklace and go for a fabulous bracelet or ring instead.  If you’ve got an exquisite necklace on, go small with the earrings and maybe just do a cocktail ring.  If an arm full of bracelets is your thing, counter balance them with fabulous earrings.  You get the idea.  You’re better off having one focal point, and one or two important pieces of jewelry than a smattering of small, meaningless pieces.   

You also want to keep scale in mind when choosing accessories.  If you are a very petite, small boned, 5 foot tall woman, you don’t want to over power yourself in a super wide cuff bracelet, or a very large, chunky necklace.  Your delicate features are going to need more delicate pieces.  Same goes with a very tall or large woman.  You will need accessories that are more substantial to look in proportion to your body.  If you put a very thin, delicate bracelet on your wrist, it will look ridiculously small compared to your larger limbs.  This is one of the most basic tips, but I’m telling you, most people don’t know it.