OOOOO! I'm gonna stomp on some toes here!
Whaddaya look like? Who do you want in your studio? Gents this applies to us the most, the ladies take great effort in grooming themselves. Unkept appearance both studio and personal will keep Joe & Jane Normal from your door... Unless of course you operate in the top .1% of the madman martial artist, this won't apply.
Long Hair? Thats OK... But, only the open minded are going to hang around and look into your classes. First impression mean a great deal to people. Is your hair neat? Do you take inventory of what hair style you keep? Military style? Gonna get some real hardcores there. No hair? Cool. How do you come accross to potential clients.. Some hair? Cool. Are you Self concious, understandable. How do you come across to the regualr Joe or Jane? Do you get a regular hair cut? Do you keep what you got neat?
What nose hair, bushy eye brows, chest, back & earhair do you got showing?! A guy in bootcamp named Schwaky(?) had the most horrendous ear covering, looked a like a Hobbit!
Do you smile? Jeez, hopefully! Brush those fangs (as the Drill Instructor would tell us). Take breath mint, can't tell you what a turn off it is to speak to someone who's breath smells like an aboriginals as*hole! Ugh!!
Is your unform or whatever, clean and relatively neat?
Do you smell? Its called bathing and deodorant... Its not Europe and its definitely not cool to have a funk. Peanuts had Pigpen the martial arts schools don't need 'em...
Do spit when you talk (I do and its horrible when your selling...! I'm ALWAYS apologizing).
Facial hair? Is it well kept and not some wild biker look? Shave, dude!
Tattoos? I got 'em. Two, in fact, but they are high above my sleeves so when I wear a t-shirt ya can't see 'em (one was a Christmas gift from my wife if you can believe it!!! Love that woman!!!)

If you already have them be aware of your appearance as overly displaying your tats can severely affect your success and tremendously limit your clientel. They're very popular these days but the attitude you pick up wth them is off mainstream as well (sometimes not a bad thing, it depends).
Trimmed toe & finger nails? Don't need bear claws men!
All I am saying here Ladies & Gents is that a sense of normalcy will definitely bring the "person you never met" far quicker than the Ulitimate Fighting Art.