Whatever you do, however nice you think people are, whatever bother it might seem, please GET A STUDIO POLICY!! And make them sign it. Things like pay on time to avoid late charges, and if you don't show, especially with no notice, yes, you still do pay, ect. Google pianoteaching, and look at the website forum of Nancy and Randall Faber. They have a whole topic on policies alone. I didn't notify anyone in order to start teaching, but I don't make enough a year to get taxed since I'm still a student myself, so my case might be different.