There are plenty of highly critical anti-gambling organizations who claim that gambling corrupts local and state governments, guts local economies, and preys upon the weak and poor. Gambling has led some to divorce and despair causing bankruptcies and even murder and suicide.
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. You can get robbed of your profits. You can get busted by the police and get fined or go to jail. You have to weigh all of the risk against the benefits if you want to become a bookie. If you decide you want to become a bookie, you might as well become the best bookie you can be.