Run your business with professionalism and courtesy. You’ll get burned once in awhile by a few dead-beats, but you’ll more than make up for it with profits. Simply don’t let the dead beats play again. How do you get customers? On a small scale you can start a football parlay at your work place.
Collect the money as the cards are being turned in and pay out to the few winners and keep the profits. Maybe build your customer base from there. Another way would be to throw a sports party. Throw a Super Bowl party with action offered. Or maybe a March Madness party. Sometimes a boxing pay-per-view party with simple wagers offered can draw some gambling interest. You can rent a banquet room, supply food and drink. Sometimes a back room of a bar or restaurant is an ideal location. Invite people with money and interest in sports.
Friends, co-workers, classmates, girlfriends, your insurance guy. Offer lines on what ever sporting events your watching. It wouldn’t hurt if someone won big; it’s good for the overall future business. These people know other gamblers and soon you will have plenty of business. Some people actually don’t mind losing. It’s a way for them to flaunt their money.