When your function is being held in a home, garden, or hall which allows you to provide a caterer of your choice, the options are numerous. First, determine what your needs and desires are. Then interview several caterers until you find one that will best meet your needs. Start early and be prepared to leave a deposit in order to reserve your particular date and time.
Second, find out what services they provide. Some companies specialize, and merely handle food preparation, delivery, and service. Some provide every service and take care of the details and coordination of your wedding, including food preparation and serving, all rental equipment, set up and clean up, liquor, beverages, bartenders, floral and other decorations. They may provide the cake or recommend a baker. They may also be helpful with suggestions of photographers and music coordinators. Other caterers may not provide all the above services, but may recommend competent people you can contract directly.
Third, check their references and taste their food before signing a contract. Read the contract carefully to be sure it includes everything you agreed on and states the total price, and check the cancellation policies. The price should include sales tax and will usually be shown as a per person price.