Once your band has gotten sufficient practice, created a press kit, demo, and have gotten some free gigs for exposure under your belt, you should consider booking a gig for your band. Start out by scoping the local area for venues that the band would like to play at. You should look into the venues’ personal style, the crowd, and the type of bands that generally play there.
Once you identified a list of venues, contact the venues and talk to its booking manager. Make sure you send a copy of the bands press kit and demo so that he can get an idea of what the band is like.
The prices paid by the booker may vary between a door, percentage of the door, or a specified fee. If your contract states that you would be paid on the number of people you draw to the venue, you might want to check in advance on how many people the venue draws on average. If you wish to advertise your gig, look into handing out flyers and advertising in local magazine or newspapers.
If the booker offers you a flat fee for the event, you would be more certain on the amount you would be getting paid. But this does not mean that you should not look into getting more people to your event, because the more people you draw to the event the more likely your chances are on getting re-booked. Always make sure payment details are discussed beforehand to avoid any unpleasant surprises.