I think bintbeled's description probably describes my taste as well.
I like necklaces to be *big* or otherwise super-showy. Basically, jewelry should be taken to the same level of over-done-ness as makeup. In a situation where "normal" evening-style make-up is apropriate, then "normal"-sized jewelry is fine. But for stage shows, etc where you need to wear drag-queen-y stage makeup, I go for big, showy, sparkly, rhinestone-encrusted things. (Like something like
this, but less expensive) or a big, coin-encrusted jangly necklace.
As for earings... I only ask that she give a lot of thought to the types of backs or wires she chooses. I have a pair of beautiful very heavy rhinestone drops that are on posts and came with plastic backs. It takes them less than 5min to slip out of their backs and right out of my ears!