Then, make sure you maintain cleanliness and order. You don't have to be anally retentive about neatness, but an organized work area translates into a sense of competence. Not only should clothes be clean and pressed, but hair and make-up should be understated. Because many people have allergies to perfumes and cologne, its use should be light if at all. Intangibles - the way you talk and conduct yourself is probably the most important facet.
Most people consider it unprofessional to chew gum in an office setting.
Likewise, it is equally important to use a soft, calm tone of voice when talking with patients or co-workers. Even more important than how you talk is what you say. It is never appropriate to talk about patients to another patient or to a co-worker within earshot of a patient. Any time you talk about a patient jeopardizes patient confidentiality. Put your best self forward when you greet your new patient - it's worth the effort.