For Aristotle, moral conduct consists of avoiding extremes. This is tied very closely to the question that you asked about the golden mean. To Aristotle, moral conduct is conduct that meets the golden mean.
Aristotle believes that we act immorally if we do something to an insufficient degree. At the same time, if we do it too much we are also acting immorally. It is only if we do the thing to the correct amount that we are acting morally.
So, for example, if do not give enough money to charity or do not spend enough, we are excessively stingy. If we give or spend too much, we are "prodigal." But if we give the right amount we act with "liberality," which is a moral action.
So, for Aristotle, moral conduct is a "mean between two vices" in which we do not do things too much or not enough.