Casual/plain form used to indicate that something seems to be the case or appears so (used to express conjecture without strong certainty).
彼は学生みたいだ。図書館でよく見かける。
He seems to be a student. I often see him at the library.
外は雨が降っているみたいだ。窓が濡れている。
It looks like it's raining outside. The window is wet.
あの映画は面白いみたいだ。友達が褒めていた。
That movie seems interesting; my friend praised it.
Used to compare a situation to something else ('as if'); indicates that something resembles another situation, often expressive or figurative.
彼女は眠っているみたいだ。息づかいが静かだ。
She seems to be asleep; her breathing is quiet.
彼の話し方はまるで先生みたいだ。落ち着いている。
The way he talks is just like a teacher's — calm and composed.
その庭は絵みたいだ。色とりどりの花で溢れている。
That garden is like a picture; it's full of colorful flowers.