First you find a master or the master finds you, or maybe you study and learn and one way or another you become enlightened then you become a guru and teacher others, like Jesus. 
Some people just don't become enlightened, as you say maybe in the next life they will, they certainly shouldn't parade around like a pope or priest, that is just fluff and ego. That is why i say there are no really master or teacher for Catholics, Muslims or Jews because their whole idea is wrong.