Comparative explanation

SHORT ADJECTIVES (big, short, long, tall, happy...).

1-syllable adjectives: add -er to the adjective

• My sister is much taller than me.
• It's colder today than it was yesterday.

Note: If the word ends: consonant-vowel-consonant, then the last consonant is usually doubled in the comparative. Examples: big-bigger, fat-fatter, hot-hotter.

2-syllable adjectives ending in -y: change the -y to -ier

• She's looking happier today.
• This grammar topic is easier than the last one.
• Why is everyone else luckier than me? 

Beware: Do not confuse adjectives and adverbs. 2-syllable adverbs ending in -y must be compared with the word more. Example: I drive more quickly (quicklier) than my brother.

LONG ADJECTIVES (awesome, difficult, beautiful, wonderful...).

Other 2-syllable adjectives: use more with the unchanged adjective

• The shops are always more crowded just before Christmas.
• Is there anything more boring than reading about grammar?
• My sister is more careful with her writing than I am with mine.

Note: The comparative of some shorter 2-syllable adjectives can be formed with -er. Examples: simple-simpler, clever-cleverer, narrow-narrower. To be sure which comparative method to use, you will need to consult a good dictionary.

Adjectives with 3 or more syllables: use more with the unchanged adjective

• Russian grammar is more difficult than English grammar.
• My sister is much more intelligent than me.
• I find maths lessons more enjoyable than science lessons.