The key is the importance. We put that word in front that we want to emphasize. You have to consider some grammatical structure, like not taking apart the article and the referred noun (Mit a csinál most lány, mit csinál a most lány are both WRONG) and choose the most important part of the sentence.
It's a good example of a question in Hungarian: question words do not have to be in the sentence-initial position, but you can hear that the speaker's pitch is going up on the question word, which comes just before the verb (this is the "focus position"). Listen to this a couple of times while you see the sentence, and you'll get a good feeling of what questions can sound like in Hungarian!