What makes a teacher memorable?

First of all, I think it's the teacher's traits. I mean that, In my opinion, a genuine teacher should do take his/her part properly. You know that nowdays some teachers educate and teach (pick educate or teach, both mean the same thing) their children wrong(?) (Meant to be a question?) Why? It's because they don't understand how to be a genuine teachers. Personally, I think that a teacher on the one hand, a teacher should be kind, calm and benevolent, but on the other hand, he or she should be strict, fair and responsible.

The wording for this one is a little weird.

(In my opinion, a teacher should set an example to for his or her pupils by own behavior.)

Try this instead:

In my opinion, teachers should model good behavior, so they can set a positive example for their students.

First of all, I think it is the teacher's traits. I mean that, in my opinion, a genuine teacher should take his part do their job properly. You know that nowdays some teachers educate and teach children wrong. Why? Because they don't understand how to be a genuine teacher. Personally, on one hand I think that a teacher on the one hand should be kind, calm, and benevolent, but, on the other hand, he or she they should be strict, fair, and responsible. In my opinion, a teacher should set an example to for his or her their pupils by own their behaviour.

(Editor's Notes:

"Their" can be put in place of "his/he or her/she" as it is a gender neutral pronoun. It's technically plural, but is also used when referring to one person.)