Who knows what comparatives and superlatives are? You may not know the words but you do use them all the time when comparing things.
e.g. Someone may be taller than someone else. 'Taller' is a comparative word. Alternatively, someone could be the tallest person. 'Tallest' is a superlative. Easy, huh? What you need to remember is that you can't use superlatives and 'most' together, as in 'the most tallest'. It isn't correct.
Back in Shakespeare's day people got away with this, but not now:
"Standard English no longer permits expressions such as most unkindest, where the superlative is marked by the preceding most as well as the -est inflection. In C16 there was no constraint on their use, and Shakespeare uses them in several of his plays to underscore a dramatic judgment."