Find someone who races and go to a large Walmart-type parking lot before it opens or after it closes. Bring some cones or just use the painted parking dividers that are already on the ground. Have your racer friend show you how to manage the corners while you follow closely behind.
15 minutes is a VERY short event so you need to be prepared to go very hard. You should have some sort of idea going into it how hard you can go for 15 minutes, but remember that it's not going to be a steady-state effort but a serious of surges and coasts.
I may be underestimating the racing experience of your competition but there may be some folks who are strong bike riders who will be happy to just pull you around thinking they will ride you off their wheel not realizing how much more work they must do at the front. It goes without saying that you don't want to be that guy either. If you go hard and can get a gap that's great but as soon as someone catches you then you need to freewheel until someone pulls around.
Expanding upon botto's point... Don't follow directly behind anyone who appears at all sketchy.
--Steve