The comparative form of an adjective is usually formed by adding -er to a one-syllable adjective or using more or less with adjectives of two syllables or more, It is correctly used only to compare two persons or items.

The superlative, formed by adding -est or using most or least, is correct when more than two persons or things are compared.

You should be familiar with certain irregular comparatives and superlatives.

Following sentence has been used incorrectly with the adjectives or adverbs. Paying particular attention to comparatives and superlatives:

              E.g. The critics who reviewed both of Amy Tan’s novels liked the second one best.

The comparative adverb “better” should be replaced to describe how the critics felt about just two novels.