Ability to follow directions precisely. Cheerful and professional attitude. Sooner or later, you're going to get yelled at, whether or not you deserve it. A dependable car is an asset. If you have one, say so in your resume.
PAs do a lot of driving.
If you have a good driving record, keep it that way, and say so on your resume. Have an answering machine, and make your outgoing message short and professional. If you have a pager, put the number on your resume. A PA doesn't have to have a college degree, though it can be helpful. With or without a degree, you greatly increase your chances of being hired if you have a usable skill and a lot of enthusiasm.