Preparation will add professionalism to the relationship and ease the performers' fears. Your letter should not be all business. Tell the performers about good restaurants in your area. People cannot perform well if their minds are on something else. Performers often tell me how much they appreciate receiving advance letters.
Letters can be a warm-up to a good performance, which, in turn, leads to repeat performances.
And good performances can add to your credibility when you ask your deacons, treasurer, or pastor for new sound equipment. Make sure everything works . When the performers finally arrive, anywhere from an hour to several hours before a performance, make sure they have someone to oversee their product table. If they provide someone to do that, great. Otherwise, ask a trusted member of your congregation to help.