If she's got an FAQ page, read it and see what she likes.
Make sure envelope/gift bag is unsealed, accurate and visible upon entry. The bathroom counter can be a good spot for this. If she doesn't go right there, let her know where it is.
Know about parking and hotel entry. If Valet is available, let her know you'll pay for it and include it in the gratuity. This is important as a lot of very nice hotels can have rif raff outside and you don't want someone tampering with her car while she's seeing you. Think of it as cheap insurance.
If you want to provide something to drink, make sure it's in an unopened container.
Ideally, have the TV off, it's easier to chat that way.
If your room is messy, tidy up before her arrival, make sure she has a clean area for her things.
Make sure you are freshly showered.
Open the door before she has to knock or leave it cracked open so she knows she's in the right place. I believe I speak for most of us when I say, we have knocked on the wrong door or maybe the right door at the wrong hotel, doh!
Greet her with a smile and kindness.
It can be nerve wracking to meet someone new at a hotel, the easier and more disarming you make it, the more fun the session will be!