Here are a couple of ways I like to prepare my couscous.
Prepare couscous by the box instructions then into the boiling water sprinkle a little chicken stock powder, about 1/2 teaspoon depending on quantity. Stock powder to your taste.
My next like is to dissolve a teaspoon or so of garlic butter into the measured boiling water (as per box instructions) then pour into the dry couscous. Garlic butter to your taste.
Both give different but lovely flavour.