Being an adult, being an authority of your subject or your subjects, and being a tutor can be rather intimidating for a student of school years, no matter how young or old they are. This is particularly the situation when you first meet them, and it may take some time before they feel more comfortable to reveal to you where they need help.
So, starting off your tutoring session with a genuine "how are you?" or something of that nature can always help. They will realize that you care about them as individuals instead of just getting help and information from you. Also, what I find helpful after finding out how they are, I always ask them "so, how can I help you today?" By asking these two vital questions, they will feel they have more control of how the tutoring session will go, and they will have their educational questions answered.