The most important thing is to play stupid, meaning, never admit to the wrongdoing.

For example, I was delivering food/pizza back a few months ago, and on my way back to the store I was stuck at a long red light at this hill, and there was no car in sight, so I made an illegal right turn on red (there was a sign that said no turn on red). Sure enough, right as I turned the cop was about 75 feet away, so he made a U-turn and pulled me over. When he asked if I knew why he pulled me over I said "No, I'm sorry", so he told me I made the illegal turn on red. I apologetically told him I didn't see the sign and wouldn't have made the turn if I knew it was there.

Eventually, he got my license/insurance/reg, went to his car.. then he asked if I was in college and whatever and just said 'watch the signs' and let me go.

Long story short, don't admit to the wrong doing, be courteous/apologetic, and play stupid.