Telling the truth works surprisingly well most of the time.
Telling the truth almost always results in a warning from me. A couple things that will absolutely result in you getting a ticket:
1. Saying you have to go poop, especially when you have passed 3 or 4 gas stations between where you started out and your destination.
2. Asking me "don't you have some real criminals to catch?"
3. Telling me you are too poor to afford a ticket as you smoke a cigarette that came from one of the 27 cartons in your back seat.
4. Telling me you pay my salary. My response: Thank you, this ticket will keep food on my table.
Those are just an example, there are many more.