When you're on vacation and someone asks you where you're from, chances are you'll tell them you're from the closest big city to your suburb. After all, who's heard of little Decatur, Georgia? You say you're from the nearest big city to Decatur, which is Atlanta, because people are likely to be familiar with Atlanta.
Marketing yourself in the voice over industry is no different. When networking with clients who may need a voiceover artist's services, let them know you are from a bigger market than your suburb. Put it on your website and on your business cards. Even if you're just starting out, new clients will put more faith in a voice-over artist from Sacramento, CA, than, say, someone from Elk Grove. People who live in smaller towns always see city people as being pros at whatever they do.
Now that you have established yourself as a voice-over talent from a major city, don't try to market yourself in the big city. That is the number one mistake that new voice over artists make when they're just getting started. They got their training, they have their hands on their first class demo CD, and then they try to compete with the big fish in a saturated market.
Instead of setting yourself up for failure, make contacts with people in the suburbs. Better yet -- start with your own! Chances are you'll know someone in your local area who knows someone who owns a business who needs a voiceover for an answering machine prompt, a radio commercial, or a corporate narration. Once you ace one gig, mention to the happy client that you are available for more voice over work in the area, if they can recommend another business (or better yet, a person) to contact.
From there, a lot of social and business networking is by word of mouth. With some diligent voiceover technique practice and creative networking skills, you should find yourself with repeat business in a few short months!