How to build a 36-bar melody from 7 repeats

Writing LONG melodies can be tough. How do you keep someone's attention for the length of that tune? One of the greatest secrets to this feat is the careful use of repetition. I've been studying a certain love song that gets 36 whole bars of beautiful, interesting, emotional melody with the careful use of at least 7 blatant repetitions. But wait... Wouldn't that many repetitions get boring? Not if you handle it the way these songwriters did (which is actually pretty darn easy, even for a...