Check the websites out, make a shortlist of girls then decide who you want to see & what you want. I'd check out some of the reviews too, and first time I'd deffo go for a girl with at least 1 positive review, even if she's maybe not one of your absolute faves. Just don't get off to a bad start.
I think the main thing is remember you are talking to prostitutes. Being shy about what you want won't lead to a good time. These girls do all sorts of stuff with loads of guys each week - they aren't sunday school teachers.
Most of them try to fob you off with a massage. If you want a blow job go get a blow job first then get a massage for the remaining time if you want. Better to run out of time on the massage.
Anybody with money is welcome. Rules erm - don't try and video it, you'll probably pay up front and don't take it all in 20p coins. Just obvious stuff really.