"What do you like better?"
Translation:Co máš raději?
Can't say any specific rules, but do not try to invent unusual word orders unless you have specific reason for that. We often accept many, really a lot, of forms and word orders, but more often then not, most of them change the meaning somewhat by strongly emphasizing a specific word.
So do not invent word orders without any reasons, it is much better to stay with the basic SVO order. That it is not so simple with adverbs, I agree. Still, just use the same simple order English uses as well for this sentence unless the Czech adverb needs some other placement.
The first link in Google https://en.wikipedia.org/wiki/Subject%E2%80%93verb%E2%80%93object