The positive form of an adjective or adverb is the basic form listed in a dictionary, e.g.” “red,” “awful” (adjectives); “soon,” “quickly” (adverbs). Adjectives and adverbs can show degrees of quality or amount with the endings -er and -est or with the words more and most or less and least.
The comparative form is the greater or lesser degree of the quality named, e.g., “redder,” “more/less awful,” “sooner,” “more/less quickly.” The superlative form is the greatest or least degree of the quality named, e.g., “reddest,” “most-least awful,” “soonest,” “most/least quickly.” Without knowing for sure (i.e., looking in a dictionary), you can often tell by sound whether to use -er/-est or more/most. Double-check in a dictionary. If the endings -er/-est can be used, a dictionary will usually list them. Otherwise, use more or most.
There are a few irregular adjectives and adverbs. For those, you must memorize how these change the spelling of their positive form to show comparative and superlative degrees. The adjectives are: “good>better>best,” “bad>worse>worst,” “little>littler, less>littlest, least;” “many, some, much>more>most.” The adverbs are: “well>better>best,” “badly>worse>worst.”