1) Adjectives are made comparative by adding -er and superlative by adding -est, following certain spelling rules.
2) Two-syllable adjectives ending in certain letters form the comparative with "more" and superlative with "most".
3) Adjectives with three or more syllables also use "more" and "most".
4) Comparatives and superlatives have specific grammatical uses and can be qualified or contrasted for comparison.