You might offer people earphones with some sort of soothing sounds being played... Nice posters are usually fairly cheap. Always keep the place really clean, and perhaps if you left a candle burning in the room a lot it would burn up any weird smells - like people's perfumes.
Have somebody rig the lights so you can dim them - UNLESS you have tube lights - you can't dim those - only incandescent lights.
And if you are doing Massage - fun book - a sort of redefinition of life - "Spontaneous Evolution" by Lipton. There's a massive amount of fun stuff in there about energies and that sort of thing but from a scientific viewpoint - it's not just a hippy book.