Have water readily available and I typically carry more toiletries with me just in case...
Soothing/sexy music is great to put me in the mood as well as my date..

(real or fake) add to the ambiance as well as minimal light.  Some providers carry a colored scarf to put over a lampshade in the room to enhance the atmosphere.   Water is good but for longer engagements, wine and some fruit & cheese or chocolate is a nice touch.  Soft instrumental music helps the mood as well as decreases any chance of playful sounds being heard in the hallway or room next door.

Reminding again, it was Toronto, Canada where escort outcalls are legal.    I talked with the lady in charge of housekeeping the best way to greet my date and here is what she did two hours before time:

1. Placed two mini baskets of Dream potpourri (sandalwood & rose) in living room of the suite and one in the bathroom.
2. Replaced regular hotel table lamps with lamps with dimmer switches.
3. Placed aromatic candles in the bedroom part of the suite and have me light it 15 mins before time.
4. Downloaded couple of really soft and romantic tunes in to my Ipod and the radio / clock in the suite was ipod compatible.
5. A small bouquet of real red roses to give to my date as soon as she arrives.

 
Hey, no need to say I had the best time.

On several occasions I had to ask to turn the TV off. It's tough to set the mood with a soundtrack of obnoxious car dealer commercials.]

This might be a bit more practical...

although being a traveling lamp saleswoman might be a cool hotel cover story...