I either do a phone interview or an email interview pre-screening. Check that they live or work in your vicinity, ask their hours and make sure they are good for you, ask about their family and the child's age, routine for food and naps, any past care and if they left someone else find out why. You are way too busy to waste your time interviewing someone in your home after work hours and find out at the end of an hour that they want you to open an hour early or some other nonsense. So ask all the basics in the pre-screening, then get to know them at the face to face interview.