I am pretty lucky in that no matter what I wear, fine jewelery (e.g. gold/silver, diamonds, sapphire, etc.) looks pretty good on me. My everyday necklace is a pretty sturdy gold chain with a little heart pendant, but every once in a while I'll switch it up for some kind of costumey deal that I got at a cheap accessories store. I can't wear earrings though, because they look bad on my ears. I love my nose ring though. So much.
The trick to wearing jewelery is finding something you are comfortable with. People only look ridiculous when they don't know how to wear that giant enamel bracelet or big flashy ring. My mother and grandmother have the most insanely flashy, unique jewelery collections I've ever seen, but they work it. Especially my grandma. Lady knows her accessories.