E.g. don't yell at them or talk to them the way like if a catastrophe has happened every time a minor imperfection in their behavior occurs. Also don't assume they are idiots which can never understand they've done something wrong (and should generally avoid) without you telling them.
I'd go as far as to say that you should not yell at a child ever. I don't see any possible scenario where punishing a child like that would lead to something productive.