One of the most important things to do after booking a gig is promoting that gig to ensure that it is not the first and last gig that you will do. Every gig is an opportunity to showcase your band and an opportunity to breakthrough the music industry. Follow through is the key not the lack of information.
If you are playing in the same venue for an extended period, it is preferred that the cycle of your audience would be every 3 weeks at least to ensure that different people are watching you every time you perform. Promote only upcoming gigs and not recent ones to give fans the impression that they can only watch you on those days and that your current gigs are already sold out. This will give you a chance to spread out your audience. Promote every show like it’s the only show. If you do not promote, nobody will come, if nobody will come, no one will want you to play again.