If you're a novice, before you climb you should think of fitness -- yours. While activity will improve it, don't rush up challenging peaks without first trying some gentler slopes. Jefferson's Rock in Harpers Ferry, for instance, is not actually a "mountain," but it's a good place to start testing yourself. It's short, but aerobically taxing, and you have to be sure-footed. The view is spectacular.
For a one-day hike up these peaks, you can probably get by on what's already in your closet. For a short first- time hike, a comfortable sneaker-type shoe with a traction tread will work just fine. Of course, be sure it's already broken in and has plenty of room for foot expansion.
Also, you should check the weather conditions in the area by calling the National Weather Service (899-3240), because your next major concern is comfort and safety. It could be affected by a sudden rain or unexpected change in temperature.
For moderate temperatures, wear a sweater over a shirt and, perhaps, a lightweight waterproof windbreaker over that. If you're too warm, you can peel down, using the long sleeves to tie the jacket or sweater around your shoulders or waist. Long pants will protect your legs from scratches and bites. (Tuck a handful of Band-Aids in a pocket in case of blisters.) Consider, too, insect repellent, sun screens and a visor or hat. Cologne and hair spray should be avoided, since they attract insects.
Those are the bare basics. For more information, contact the Potomac Appalachian Trail Club at 1718 N Street NW, Washington 20036 (638-5306). Open weekdays from 7 to 10 p.m., it's staffed by knowledgeable and dedicated volunteers. It also has an extensive collection of maps and guidebooks for sale (most published by the club).
Park rangers and foresters are also valuable sources. Or try a group trip. These are regularly arranged by the Appalachian Trail Club and by other clubs. Your first ventures need not be alone or dependent on car ownership. Club trips are so satisfying that many people hike no other way.