1. Using "-er" or "-ier"
This applies to most adjectives with one or two syllables.
* Short Adjective + "-er": e.g., tall - taller, fast - faster, big - bigger
* Short Adjective ending in "-y" + "-ier": e.g., happy - happier, easy - easier, heavy - heavier
2. Using "more" or "less"
This applies to adjectives with three or more syllables and some two-syllable adjectives.
* "More" + Adjective: e.g., beautiful - more beautiful, interesting - more interesting, difficult - more difficult
* "Less" + Adjective: e.g., happy - less happy, interesting - less interesting, difficult - less difficult
Exceptions:
* Some two-syllable adjectives can be compared using both methods (e.g., clever - cleverer or more clever).
* Irregular adjectives have unique forms (e.g., good - better, bad - worse).