Hotel won't give a shit if your discreet about it. Xo is a good well reputed agency so don't fear anything about police or whatever.
Otherwise if you search this forum you will be able to find all the infos you need. But in a short version..
1) Put donation in plain sight
2) Shower before she arrive
3) Be a nice guy, polite, look happy to see her. Buying a bottle of wine or something to drink is not mandatory but can help make the introductions go smoother.
4) Ask her before starting up what she like and dislike. If for instance you would want to do cim (cum in mouth), ask her and make sure to know if its extra or not. It depend on the lady.
5) Do not be too shy, even if it will be hard. You are here to have a good time and not make her feel awkward.
6) Giving a tip if you had a good time is always well received but not mandatory or expected.
Otherwise just enjoy your time man. I mean with Xo things should be smooth.