2- light:
Light some candles. There's something very relaxing about candles, so it's a good idea to light a couple around the room
If possible, turn the lights down low or off completely and work only by candlelight. You want the person receiving the massage to be so relaxed that they're almost asleep by the end, so the darker it is the better!
Use candles with relaxing (but not overpowering) scents, such as lavender or sea breeze, to contribute to the overall experience.