First and foremost address the issue of overspray. How are you ventilating the room? Some companies offer airbrush overspray booths, some salons use filter fans, some install vent fans in the ceiling if the room is sealed. If you do not address this issue you will have headaches, you and your clients will be breathing in the spray, it will get in to your air conditioning system and clog it up and if you do not have an fully enclosed room it will make it's way over to the other rooms and leave a nice brown film on whatever it lands on.
Next after you have addresses overspray it is a good idea to protect your walls. I have seen people hang bamboo blinds on their walls. It gives the room a nice spa type feel. I have also seen shower cutains on the walls but that does not look as nice.
It is good to have a rolling cart if you are using an airbrush compressor. If you are using a turbine it is better to just leave it in the floor.
You know in aerobics class how they have those plastic stair steppers? That is another good thing to have. It will save you from being on your knees a whole bunch. Put the customer on that and get one of those short rolling chairs they use in the nail salon.
There are great products on the market in the way of disposable underwear. I have noticed most clients are receptive to wearing in an old bathing suit or just doing it in the buff. That would be operators choice on what is acceptable or not.
Another great thing to have is a protective non-slip floor mat.
Drying is another issue. Some of the booths have a built in drying system. If you are doing airbrush on a budget you can purchase one of those hair dryers that have a hot cold setting. You can leave your customer in the room and have them use the blow dryer on their body to dry any areas that still feel tacky.
It could not hurt to have a wavier form either!
NAtional Tanning Training Instutitue used to have an online training course for airbrush. You could download the manual for free. I think it was a great read and had lots of good info. Try their website to see if it is still there. I think the address is
www.ntti.com