～は～より～です

AはBより～です compares two things: "A is more ~ than B". A, the thing you are talking about, takes は; B, the yardstick, takes より; the adjective comes last, in its ordinary form.

Japanese has no "-er" or "more" here. より does all of it, and it goes after B, where English puts "than" in front.

• × 猫は小さいです犬より → 猫は犬より小さいです

Swapping A and B

Whatever is before は is the one described. Swap the two nouns and you need the opposite adjective.

Saying what you prefer

With すき好き, the person takes は and the thing preferred takes が. The thing after より is the one you like less.

To answer "which is more ~?", use より〜～のほうが instead: でんしゃ電車よりばすバスのほうがやすいです安いです.