I've got a question regarding the emphasis in this sentence. Am I correct to assume that the sense of the sentence is "It is good waiters that Peter is looking for"? Is there a general rule where to look when I want to find the emphasis in a Hungarian sentence?
Yes, you got it!
I'm sure there are several rules on emphasis. Generally, the important stuff tends to be close to the front of the sentence. Another important one is words that are before the verb, like in this sentence - the object is before the verb. Yet another is when a prefixed verb gets split. It can put extra emphasis on what is before the verb. One way to look at this is that the stressed words want to be as close to the root verb as possible. They kick the preverb out of the way. When the verb is not split, it usually has at least some emphasis.
Péter elmegy iskolába - Péter goes to school. - Very neutral.
Péter megy el iskolába - It is Péter who goes to school.
Péter iskolába megy / Iskolába megy Péter - emphasis on school.
Iskolába Péter megy - Both school and Péter emphasized.
If you can, try figuring out the most neutral order of the words, then figure out what can be achieved by mixing them up.
The two answers given here have completely different meanings in English 1) Peter is looking for good waiters 2) Peter is searching good waiters......(without "for") "searching good waiters" would indicate that Peter is going through the waiters pockets