Roy C. Swab, a volunteer who's been watching inaugurations since 1933, says the most important thing is "keeping the feet warm -- one or two pair of wool stockings and some kind of boots. Also, a warm knit cap for the head and mittens or gloves for the hands."

D.C. Police Sgt. Joseph Gentile advises that you "be patient, because traffic will be congested and you may have to walk several blocks." Anita Gottleib, a veteran of the Carter inauguration, suggests that you find a friend with an office or home window view of the events and "offer to bring food for a party." And Judy Doctor, a Montgomery County consumer official, cautions that you should "expect to overpay for souvenirs that may help you remember the event but probably won't be very good quality."

The advice is aimed at helping residents and visitors survive Inaugural Weekend, whether they plunge into activities or try to steer clear.

Many events are by invitation only. Some others require high-priced tickets. But there are free activities open to the public, including a concert at the Jefferson Memorial at 5 p.m. Sunday and the inaugural parade, scheduled to begin at 2 p.m. Monday, along Pennsylvania Avenue.

The inaugural ceremony on the West Front steps of the Capitol at 11:30 a.m. Monday is a public event, but only those with tickets will be allowed onto the Capitol grounds. The closest anyone can get without a ticket is the area around the Capitol reflecting pool, which is across the street from the Capitol steps where Chief Justice Warren Burger will administer the oath of office to President Reagan.

If you don't have a ticket, you would be smart to skip the swearing-in and go directly to Pennsylvania Avenue to find a spot to watch the parade, which will feature 37 civilian bands, 6 military bands, 35 horse units, 5 marching units, 1 dog sled, 15 military units, 7 floats and 2 choral groups.

Anyone who gets anxious when surrounded by large numbers of people probably should skip the parade, too. An estimated 300,000 people are expected to crowd into position along Pennsylvania. Some of them will be in the bleachers erected between 13th and 17th streets. The three types of seats sold to the public were $12.50 reserved, $75 preferred and $100 premium. Those without bleacher seats are expected to find viewing spots on the sidewalk along Pennsylvania between Third and 14th streets.

Pennsylvania Avenue will be closed to vehicles from 9 a.m. Monday until after the parade ends, probably about 4 p.m. Pedestrians will be allowed to cross the avenue until 1 p.m., if it doesn't interfere with pre-parade activities. No pedestrian crossing of the avenue will be allowed from 1 p.m. until the parade ends.

If you attend any outdoor events, you should dress to protect yourself from the extremely cold weather that is forecast, according to Dr. Sidney M. Wolfe, a consumer health activist who has studied cold's effect on people.

"Anyone who stands outside very long has to be careful to insulate himself from the cold," Wolfe said. He recommended multiple layers of clothing, a cap, mittens or gloves, insulated boots, a weather-resistant jacket and plenty of warm liquids.

"But not much alcohol, if any," Wolfe said. "Alcohol causes the blood vessels on the surface of the skin to dilate and increases the loss of heat from the body."

Wolfe also recommended moving around as much as possible. If you are trying to hold your position near the front row, you can exercise in place, he said, by periodically standing up on your toes several times and stretching your arms -- just as though you were taking a seventh-inning stretch at a summer baseball game.

Officials said 19 comfort stations and 3 first aid facilities will be available for those attending the parade. They recommend that you note the locations when you arrive so you know where to find them.

Three locations also have been designated to handle the problems involving lost or missing persons. Members of the Metropolitan Police Department Youth Division will staff problem centers at the U.S. Courthouse, Constitution Avenue and John Marshall Place NW; National Archives, Pennsylvania Avenue and Eighth Street NW; and at the District Building, 1350 Pennsylvania Ave. NW.

Here are tips for coping with the crush of the crowds coming into the city for the celebration: Use public transportation. Keep in mind that you must have exact change for buses. To save time when riding Metrorail, purchase round-trip Farecards. Visitors should know that each person must have a Farecard and that Farecard vending machines will accept coins and $1 and $5 bills but nothing larger than that. Metrorail, which normally closes at midnight during the week, will operate late Monday night; the trains will run until 1:30 a.m. Jan. 22.

* To avoid crowded trains, Metro urges that riders leave events early or "stay downtown for a while afterward" and take in some museums. Seven museums of the Smithsonian Institution, for instance, will be open 10 a.m. to 9 p.m. through Monday (normally they close at 5:30 p.m.). One exception is the Air and Space Museum, which will close at 1 p.m. Monday to prepare for an inaugural ball.

* Tag small children with name, address, phone number and other helpful information in case they should become separated from you. Bring a book or a game to amuse children who may get restless waiting.

*Empty purses and wallets of unnecessary credit cards. Carry a minimum amount of cash and keep it inside your clothing. CAPTION: Maps 1 and 2, SEATING FOR THE INAUGURAL PARADE; THE 1985 INAUGURAL PARADE. By Dave Cook -- The Washington Post