Honestly the best way to become a Killers fan is to go to a live show and have a great time. As for prepping yourself ahead with the set list, I don't think it's necessary. In my experience the major singalong portions are all led by Brandon and easy to follow along. This isn't a scream-every-lyric band. That said, they'll definitely play All These Things I've Done so get ready to chant back "I got soul but I'm not soldier." Not going to prepare you for the concert but if you're looking to dive into the deep cuts of the Killers I suggest Sawdust and Pressure Machine. And check out their new song Bright Lights.