みたいだ

みたいだ at the end of a sentence means "is like", "looks like": one thing resembles another. It goes straight after a noun, with no の or だ in between, and changes like a な-adjective: みたいです, みたいだった, みたいじゃない.

• × 図書館のみたいだ → 図書館みたいだ

"Like" or "seems"

The same みたいだ also makes a guess: "it seems". After a verb or adjective it can only be a guess. After a noun it can be either, and the context decides.

まるで in front of the noun leaves only the "like" reading.

みたいだ or ようだ

ようだ means the same in both senses and belongs to writing and careful speech. みたいだ is the conversational form. ようだ takes の after a noun: ゆめ夢のようだ against ゆめ夢みたいだ.

Before a noun, みたいだ becomes みたいな, and before a verb or adjective みたいに.