Have them fill out an application. Ask them about their prior employment. How long they worked there? Why they left? If you need experience, like a crew leader, ask them what specific experience they have? Details like what kind of trimmer have you used? What mower did you use on your last job? How many lawns would you mow in a day. What type of lawns were they? Make sure you check thier references? Did I say, Make sure you check their references. Do you have a drivers license? Have you had any tickets against your drivers license? Check their driver license record. Oh and make sure you call their previous employers.