Before anything, here are the three questions you should always ask:

How may I help you? or What can I do for you?
This establishes, psychologically, that you are in charge here, however, it is perceived as you being polite. Like a teller in a fast food drive through, though they are doing as you ask, they are controlling the situation.

Once the officer has responded to your first question, no matter what the response is, next question: Am I under arrest?
99%(est) of the time, it will be no.

Am I free to leave?
If they said you are not under arrest, this question must be answered yes. Why? If at any point you feel or are told you are not free to leave, you are immediately under arrest. In fact, being under arrest is not a matter of the officer's intention, it is a matter of your perception.

Finally, never tell on yourself. Don't apologize for the stop sign you blew through or tell them you were only doing 65 when you were doing 80 or any of that. When asked if you know why he pulled you over, say no, I'm sorry, I don't and jump into the above questions.