On her first trip to Europe, Ann Waigand, a Washington travel consultant, headed for London to tour the city extensively. Or so she thought, until friends back home asked her about the Elgin marbles, the famous sculptures from ancient Athens in the British Museum.

"The Elgin marbles? I hadn't even known they were there," she says. It was a lesson that quickly convinced her to read up in advance about any place she planned to see.

On Tuesday evening, she begins leading a six-session course, "Learning Through Travel," offered by the University of Virginia's Falls Church Regional Center. The classes are aimed at travelers who, like Waigand, want to prepare themselves properly for sightseeing abroad, and she promises to provide practical guidelines for doing just that.

Waigand is a director with Academic Travel Abroad of Washington, a 35-year-old organization that specializes in arranging study trips abroad for colleges, museums and other educational institutions.

When you plan ahead, says Waigand, you don't make the mistake of missing the Elgin marbles.

A six-session course in how to prepare for a trip could sound like overkill to travelers who may prefer spur-of-the-moment holidays. But, says Waigand, "If one delights in learning, then preparing for a trip can be half or more of the fun."

Before a recent trip to Japan, she read about Japanese religions, an important aspect of life in that country. As a result of her studies, she says, her visit was much more rewarding. For one thing, she knew the difference between a Buddhist temple and a Shinto shrine and could understand many of the symbols displayed in them.

In her instruction, she will, of course, advocate reading a great deal about the country to be visited, and she will offer suggestions on where to find the right books. On her own trips, she starts with standard sightseeing guides and moves on to more specialized subjects, such as history and art.

While she's actually traveling, she prefers to read novels set in the locale she is touring. It's fun, she points out, to read about somebody on a Nile cruise when you similarly are sailing on the river.

She finds she keeps reading about a country even after she is back home. After the Japan journey, she started reading Japanese literature in translation.

But she suggests going beyond books, urging travelers to sign up at a college or the Smithsonian Institution for classes dealing with the history, art or other aspect of a place they are planning to tour. You also should consider a foreign-language class, if only to learn a few basic words. With a language, "anything you can do is worthwhile."

And if she's unfamiliar with a nation's food, she'll seek out an ethnic restaurant in Washington to sample the menu.

Class participants will receive reading lists for specific destinations and information on travel resources in the Washington area. The classes meet for the next six Tuesdays from 7:30 to 9:30 p.m. at George Mason Junior-Senior High School in Falls Church. Registration fee is $35.

For more information and registration: University of Virginia Falls Church Regional Center, 698-5649. CONCORDE BARGAINS:

If you have always wanted to fly transatlantic on the supersonic Concorde but couldn't quite come up with the hefty fare, consider one of the "Concorde the Atlantic" charter packages to London offered out of Baltimore/Washington International Airport.

The packages include a one-way charter flight on the supersonic Concorde and return travel on a regularly scheduled British Airways flight (or vice versa); six nights in a London hotel with continental breakfast; airport/hotel transfers; a special tour; and one night at a theater -- all for a price that is less than the standard one-way service on the Concorde.

The current one-way Concorde fare is $2,423. The charter packages range from $1,849 to $2,099 per person (double occupancy), based on the departure date. Flights with space still available are April 17, April 25, May 18 and May 25. On the April 17 and May 18 departures, the flight to London is via subsonic aircraft, returning on the Concorde. On the other two flights, the initial leg of the trip is via the Concorde.

"Concorde the Atlantic" packages are offered by The Travel Committee of Owings Mills, Md., a major tour wholesaler. Reservations can be made through many Washington travel agencies, including Omega World Travel, VIP Travel Agency and Waters Travel Service. BASEBALL FANTASIES:

Baseball fans who may once have dreamed of a career in the major leagues can spend a big-league week in November playing ball with a group of former Yankee greats at the Mickey Mantle/Whitey Ford Fantasy Baseball Camp in Pompano Beach, Fla.

It's an adults-only camp open to male and female baseball enthusiasts. The participants, limited to 50, will get daily fundamental instruction from the two Yankee stars and their former teammates, and there will be a daily intra-squad game.

Scheduled for Nov. 10-17, the camp is priced at $3,000 per person, which includes accommodations at the Sea Garden Motel in Pompano Beach; breakfast and lunch daily; a replica Yankee uniform with the participant's choice of number; 50 baseball trading cards with the participant's own picture and statistics; and a videotape of the "Fantasy Finale" game between the pros and the amateurs.

For more information about this and future baseball camps: Great American Sports Camps, 5764 Paradise Dr., Suite 7, Corte Madera, Calif. 94925, (415) 924-8725 or (212) 509-5599. CAR RENTALS IN RUSSIA:

It's now possible for travelers to Russia who want to see the countryside to rent a Soviet-made car in Moscow and drive it to Leningrad -- or rent one in Leningrad for the trip to Moscow.

The distance is 400 miles over a major highway between the two cities, but you should expect to spend a minimum of two days on the road.

Guido De Gorgey of Russia Tours, which is offering the rental program, suggests spending the night in the city of Novgorod, about 120 miles southeast of Leningrad. One of Russia's oldest cities, it is noted for its surviving old-Russian architecture.

The basic rental price begins at $12 per day, but there are additional charges for mileage and gas. The cars can be rented in one city and dropped off in the other.

For more information: Russia Tours, 175 Fifth Ave., New York, N.Y. 10010, (212) 475-7773. MUM FESTIVAL:

An annual floral treat is the fall chrysanthemum festival at the famous Longwood Gardens in the Brandywine Valley area of southeastern Pennsylvania.

More than 15,000 mums in 40 varieties will be displayed in indoor conservatories from Nov. 2 through Nov. 24. Huge bunches of the flowers -- yellows, pinks, whites and bronzes -- cascade from walls and pillars, and others fill vast hanging baskets. The "Cultured Chrysanthemum," another greenhouse display, traces the history of the mum from its Far Eastern origins to its use today.

The theme of this year's festival is "The World Around," and there is a varied agenda of music, dancing and handicraft exhibits from many foreign nations.

The gardens, about 110 miles from Washington in the town of Kennett Square, Pa., make a nice weekend outing. The lovely Brandywine Valley is home also to several notable museums, including the Winterthur Museum and Gardens (open Tuesday through Saturday, 10 a.m. to 4 p.m., and Sunday, noon to 4 p.m.).

The quickest route to Longwood Gardens is north on I-95 to Wilmington, Del.; north on U.S. Rte. 202 to U.S. Rte. 1; and west on U.S. Rte. 1. The festival is open daily from 10 a.m. to 5 p.m. Admission is $5, adults; $1, ages 6 to 14.

For a list of festival performances and demonstrations, send a self-addressed stamped envelope (business size) to: Chrysanthemum Festival, Longwood Gardens, P.O. Box 501, Kennett Square, Pa. 19348-0501. For information: (215) 388-6741.