By Alina Dizik Local commercials can come across as cheap, amateurish and downright goofy.But those are their good points.Big national brands can spend a lot of money on commercials that are almost as entertaining as the shows they interrupt—big casts, continuing story lines and stellar production values.Small businesses can't afford any of that. So how do they fill 30 seconds without breaking cardinal rules of marketing, like not boring viewers and not overloading them with information?The answer, say marketing experts, is to embrace the limitations of local ads. Small businesses should play around with unusual ideas and approaches and not worry about how goofy they may seem. Cheesy slogans can plant a business's name and phone number in viewers' minds, and oddball scenarios can make people remember selling points about a product line."When you don't have access to top talent and top producers, it comes down to experimenting," says Chris Tuff, a senior vice president at 22Squared, an Atlanta advertising agency.There's another big reason to experiment: Local commercials can have a much longer life span and broader reach these days on sites like YouTube and Facebook. A small, local business can find itself with a national following if its ad goes viral—and the ones that take off tend to be those that aren't afraid to take chances and look a little silly.An amateur performer doing a rap about an Alabama-based furniture shop became a viral hit despite low production values, says Mr. Tuff. The same happened with a Chattanooga, Tenn., golf shop that ran a commercial where the owner repeated "We buy golf clubs" into a wobbly hand-held camera for a humorous effect."What ends up getting shared online isn't always content with the best production or story line, but what resonates with the target audience," Mr. Tuff says.As businesses experiment, though, they should remember the basics—like keeping things simple. Ellis Verdi, president of DeVito/Verdi, a New York-based advertising agency, says businesses should stick to short story lines and concepts that are easy to execute with one or two actors. And rather than buying a 30-second slot, consider purchasing two 15-second spots, which can run more frequently.Along the way, be sure not to overload on information—share only the most necessary details about the business, such as the location and what you have to sell. "You don't want to make people's eyes glaze over," says Roger Berkowitz, who heads Boston's Legal Sea Foods. "If you give too much information, you are going to turn people off."When Legal was looking for an affordable campaign to appeal to a younger generation, it didn't explain the company's offerings in depth. Instead, it focused on the basic idea of fish and used YouTube and other footage of people doing silly things to create a humorous campaign: Fish is brain food, and see what happens if you don't eat it?The company also used humor in an ad that starts out like a public-service announcement to save wildlife before introducing the chain and urging consumers to eat seafood.Messages in ads can get even simpler. For instance, after a hurricane, a credit union on New York's Long Island used photos of the devastated area and a classical-music soundtrack to send the message that it was still lending despite the calamity, says Mr. Verdi.Focusing on an image of a product or location can pique costumers' interest to find out more without burdening them with lots of facts. Local landmarks or scenery can also be a subtle way to show that the business really understands the viewer—and asking residents to be featured in the commercial can remind viewers that they are supporting a small business, says Franklin McMahon, founder of Franklin McMahon Studios, a Portland, Maine, creative agency.What about the old standby—focusing the commercial on the founder or a local celebrity? Experts say it can be effective but can present problems if viewers think the star of the commercial is constantly present at the business to deal with customers.Whatever approach a business takes, the pros say, the bottom line is don't compare your efforts to high-powered national ads. Your viewers won't."People are more forgiving with local commercials," says Mr. McMahon. "So it's a little bit easier to shine." Ms. Dizik is a writer in New York. She can be reached at reports@wsj.com.