The concept of error gravity and dichotomies like global vs local , interlingual vs intralingual, syntactic/semantic errors need to be taken into account.
Do NOT think or talk in terms of errors and mistakes. Talk to your students in terms of "here is a better way to say it."
There is a lot of research out there in cognitive psychology about the negative aspects of calling things "errors" and "mistakes." Better to think in terms of "here is a way to achieve more sucxcess."