Chris has good advice. I don't have much in the way of teaching experience, but one thing I would do is not avoid the "advanced" scales in the beginning. That's not to say that you shouldn't start with the easier ones, but I know plenty of beginner students who were "afraid" of the more advanced ones. There's nothing conceptually harder about them - in fact I find them easier.
In teaching me scales, my teacher told me how Chopin would teach his students C major last, because he found it the hardest. While I don't know if I'd go to that extreme, I can kind of see his point - with C major you're "lost in a sea of white". Other keys have black notes interspersed which can act as "markers" to help you know where you are. For example, with E major RH ascending, you always tuck the thumb when you're moving from a black key to a white key - simple.
Even now, I find the keys with lots of black notes to be easier when it comes to scales.
What you are is an accident of birth. What I am, I am through my own efforts. There have been a thousand princes and there will be a thousand more. There is one Beethoven.