Вы не так сморите. - You are looking in the wrong way. (The way you are looking is not that way /which was expected/.)
Вы не туда идёте. - You are going the wrong way. (The way you are going is not that way.)
Вы взяли не ту книгу. - You took the wrong book. (You took not that book.)
Это не тот автобус. - It is the wrong bus. (It is not that bus /which you need/.)
Вы взяли не свой ключ. - You've taken the wrong key. (You've taken not your's key)
Ты купил не такие марки. - You've bought the wrong stamps. (You've bought not those stamps.)