well, in my experience, the ones that exude sexuality. You know, you can tell, they prowl around, they don't walk......
But then again, what do YOU determine to be "good in bed"? Everyone's tastes are different. I know I don't want a woman who wants to be pounded hard. Or bossy, but she needs to be open minded (meaning you won't ever hear the words "you want to do WHAT"???? lol)...I'm not talking about a midget and a goat or anything, but if you have an idea about say fucking in the change room at la senza she won't freak out on you....
To be honest, the ones that are really flirty, dress in low cut tops to show off their boobs, wear skin tight jeans and CFMs are usually quite boring in bed. They types seem to spend all their sexual energy in how they look, not how they are...