I have been taking private tuitions for School kids for almost 8 years now.
Mine is a very simple strategy, I've observed humans learn and learn fast when they enjoy something or when they can relate to something.
I make sure whatever I teach I don't just read it out of the books , but I somehow try to give them real life examples about it, and by real life I mean examples from the student's own life. So that they can relate the concept easily. For this reason I also take out the time to personally know the student better. This way they open up to me and they I am also someone they can talk to anytime for anything.
I never try to scare or punish my students. A punishment for my student would be an hour extra with me which doesn't involve studying.
There are a few things which just needs to be remembered or mugged up. For such topics , I suggest using Abbreviations if it's a formula or set of items. Otherwise writing something again and again helps a lot too.
Hope these help you. :)