I did a New Years Eve disco themed party once and this guy asked me to play "Brick House" so I played it. After that, every 10 fkn minutes the guy would come up and ask for "Brick House" again until finally I had no choice but to tell him to get the fuck outta my face.

You don't need security BUT you gotta make sure that you set them straight from the jump because once you let 1 kid get behind your stuff they flock. Back in the days when I used to have CD bags< I would spread them out next to me on a table so I could just look down and see them all, I had 300 cds and there was always 1 kid that would ask to look at the cds, within 10 min now there is a gathering of 10 kids and they are grabbing them and taking them out and it becomes a mess, you may sound mean but you have to set em straight or else it turns into a mess.

In terms of preparing, its knowing your music and going through it ahead of time. I really only have a few playlists set up. If I get a request list for an event I will set up a playlist with their requested songs and that's it, everything else is on the fly. Nothing impresses people more than when they request a song and 2 min later you are mixing it in with the song that was playing when they made the request.