Meet with the choir leaders of all the choirs that will be involved in the festival. Plan an itinerary of songs for the festival as well as a date and location. Determine which choir members will be given soloist positions and for which pieces. Record the information decided.
Set a rehearsal schedule for the festival, agreed upon by choir leaders. Arrange for the musical accompaniment to attend rehearsals. Rehearse with all participating choirs for the festival at least a month in advance, ideally several times a week.
Alert the community to the date of the choir festival by printing fliers. Establish a website or Facebook page for the festival, alerting all members of the community to the event. Determine if you are going to sell tickets to the event or not. Explain that this is either a free event or specify where attendees can buy tickets on your website or Facebook page.
Contact local bakeries, wineries and restaurants for sponsorship for the festival. Explain that they need not donate any money, but just donate food and drink for the reception after the performance.
Arrange for tables and decorations for the food area. See if local schools or restaurants can donate tables to display the food on if you don't already have enough.