That's an easy one for me, because it's taken years for me to learn it. Good grief! Don't ask....
The Number One Rule to Always do:
Teach your students your routines and then practice. And practice. And practice. Don't stop practicing until they do it EXACTLY the way you want them to.
Here's why. If you teach them and have them practice it once or twice right then and there, you will spend the rest of the year correcting them. Or frustrating them. Or getting frustrated with them. Very few of us know how to do things well after the first or second try. Our students don't either.
So trust me on this one. Practice it as much as you need to, even though you might think it's redundant. It's not, until they all get it. You will be SO glad you did this!
Took me ages to learn.
Have a great Sunday!