Correct position of adverb?

That would depend on what were meant by individually. In fact, i can see no good reason to use the word in that sentence, unless it meant the instruction of students, one at a time, individually. In that case, the way it is used there does not make that clear.

I agree with Setanta. Perhaps you mean...

Besides such valuable experience, I also worked at an after-school study centre where I taught English and general learning skills on an individual basis.