Since Cyrous Abedi opened his designer dress shop in Old Town Alexandria four years ago, he has learned many lessons about running a small business, from marketing to accounting to sales. But the only one that's threatened his shop's existence is security.

He said his front window has been broken 20 times, five of them within the past three months. Each time, he said, he loses $6,000 to $10,000 worth of merchandise. The sign displaying the shop's name, The Look of Europe Inc., is long gone. Abedi said that sometime last year he got tired of replacing it.

His storefront on Pitt Street is somewhat isolated at night, so it's an easy target for break-ins.

And because so much of his business comes from walk-by traffic, especially at night when Old Town is full of tourists and diners, he doesn't want to put bars on the display window. "It would be like a jail," he said.

To say crime is Abedi's biggest problem is an understatement.

"It's my only problem," he said. "I don't have any other problems."

Like many small businesses in and around the city, Abedi's shop is vulnerable to theft. And as the stores get more crowded during the holiday season, their problems increase. Not all the problems are as dramatic as Abedi's, but stemming shoplifting requires constant attention by staffers who must watch every person who comes in the door.

Because shoplifting and other crimes increase dramatically during the busy holiday season, the Washington police department last week added a special detail of police recruits who will patrol shopping areas through December.

Year-round, the city police and other local police departments will look over businesses to give advice about bars, locks and alarms. They will also offer basic security advice: Know who has the keys to a business and make sure alleys are well lighted to cut down on hiding places. They also suggest that retailers keep at least one cash register near the front so employees can watch shoppers.

"Running a retail operation makes you very concerned about security," said Alain Chetrit, whose store, Silouette/Hugo Boss, has locations in Georgetown, Chevy Chase and downtown Washington.

"Your staff should devote at least 30 percent of their time to protecting the assets of the company and the rest of the time selling."

He said his stores have had less of a problem with credit card losses and bad checks in recent years because of better technology for detecting them. But in terms of theft, "It's no worse this year than last year -- it's been steadily bad," Chetrit said.

Chetrit said he keeps "one more person on the floor than we would have if this was a perfect world. ... We talk to everybody who comes in the door, we always offer help, so people know that ... they're not being totally ignored."

Some smaller shopkeepers find they have to take more drastic measures.

Security ranks as a top concern for Louise Cummings's shop, Daisy's Fashions, on H Street NE. But she said that after three years in the neighborhood, she's learned how to cope with crime. She keeps her door locked.

"I have no problems," she said. "I don't let anybody in except the ladies who shop here. And I don't let in any men unless they're with their wives."

The dresses and hats she sells are worn by older women, Cummings said, so she has no qualms about keeping suspicious-looking men out of her store.

Cummings and her niece, Patricia Higgins, opened the small dress shop three years ago after doing a market survey and finding a need for this type of operation. To succeed, they've learned a few lessons along the way.

After a few dresses were stolen, on each item they put detectors that sound an alarm if they are taken through the door. After Higgins was told at gunpoint to empty the cash register when she was alone one day, they started locking the door and controlling who comes in.

While some young men complain when she wouldn't let them in, most of her customers like it. "They feel comfortable," Cummings said.

Like most shops in the H Street neighborhood, Daisy's Fashions is protected with iron gates that fold, accordion-like, out of the way during the day.

Not everyone can lock the doors, though. Another H Street shopkeeper, who asked not to be identified, said locking his door is out of the question. The health of his business, selling audio equipment, cassette tapes and other small items, depends on the flow of traffic through the store.

"When you see a retail business that has to lock their doors, it's a big problem," he said. "That's when you pack up and go into business somewhere else."

Discouraging shoplifters is simple, he said from behind a four-foot tall, three-foot wide counter that spans the length of the store: "Keep everything out of reach."