Make sure she is into it, otherwise it could be a big turn-off. I don't know any websites but when I do it I usually go down pretty slowly, kissing my way down, keeping a relaxed atmosphere. It's not too good just to kiss her once and then jab your head between her legs the next instant.
The important thing is for her to feel comfortable with it. If she's relaxed she can just focus on enjoying what you give her. Then it's mostly trial and error, see what she responds best to and do it. Does she like it when you finger her at the same time? Does she like when you use lips, tongue and stuff or just the tongue.. does she like when you suck gently on the ****oris? Ask her what feels good if it's a LTR girl.
