Use a comparative adjective when you are writing about the difference between two of something. Use a superlative adjective when you are writing about three or more of something. Comparative and superlative adjectives usually take “-er”/”est” suffixes if they are one syllable long (or two syllables ending in -y), and “more”/”most” if they are two or more syllables. Comparatives are structured around the word “than.”

We also use comparatives for several other purposes. We can repeat the same adjective twice to show a gradual increase in something (“Things are moving faster and faster these days.”) We also use pairs of comparatives to show a dependent relationship between two things (“the bigger, the better,” “the faster you go, the quicker you will get there.”)
Unlike comparatives, superlatives always take the definite article “the,” because there is only one superlative: the biggest, the best, the most expensive. Sometimes these are qualified with prepositional phrases: “the biggest of the three,” “the biggest in the country,” “the most expensive on the table.”

The blue car was more bigger than the red one.The blue car was bigger than the red one.
The gold ring was expensiver than the silver one.The gold ring was more expensive than the silver one.
It was the bigger in the world.It was the biggest in the world.