A grilled cheese sandwich is an artifact of poverty. As such, it is constructed using two slices of white bread (30% of the time, one piece will be a heel of the loaf), a smearing of margarine on the sides that meet the pan, and a single slice of pasteurized processed American in between. Grill to desired brownness, or until Chico and the Man returns from commercial break, and enjoy.
Not hard.
Actually, I butter two slices of bread on one side. Place in pan butter side down. Place 2 slices of Sargento's swiss cheese on said bread. Place other slice of bread on the cheese butter side up..
LOW heat, let it cook for about 3 mins, flip..about 3 mins..check to see each side is nicely browned. If it isn't, continue to flip every minute or so until golden brown..
For a different experience, although it's still very good, use mayonnaise instead of butter..