Choosing a venue. Accurately predicting the size of the audience is difficult, even for experienced promoters, and it takes a bit of luck, along with lots of information, to make a reasonable guess. Find out how big the crowds have been at the act's last few shows in towns in your area. The chairs, stage platforms, dressing rooms, kitchen, and equipment may cost extra. Be sure to ask.
Publicity is the promoter's responsibility.
Professional acts will be able to provide you with promotional materials. They should do this automatically, but they may forget, in which case you must remind them. Be sure to get promotional materials, as well as posters, soon enough to be able to use them effectively. Four to six weeks before the show, contact monthly publications which have events calendars for your area. This is also the time to announce the show in publications outside your local area, giving people who will have to come a significant distance time to make plans.