1) Be prepared! This is probably the most important thing. First, bring any electrical device. Something bigger than a phone. Maybe an iPad or a computer. That way, if your kid has any homework to do, then you're well prepared. You might want to bring a pencil, graph paper, and lined paper. Another really big important thing. And depending how long you're tutoring, you might want to bring a water bottle. If you're going to be staying longer than an hour, then you can bring maybe a snack or a meal, depending how hungry you are! ;)
2) Let them do the talking. When you first meet them, they might be really shy, so make sure that they do more of the talking. That way, they don't feel that you're rushing your lesson, if you know what I mean. And don't afraid to ask questions; just make sure that you don't ask TOO MUCH...
3) Email the parents before your tutoring session. Maybe like a day or two before. Ask them some personal questions about their child. If the child is really falling behind in school and why, things like that. You might even want to ask if the child has any allergies. :) The parents will really appreciate it.
Hope you found these tips helpful. Thanks guys!