Depends what you want to do. If you want to try and talk your way out of the ticket on the spot, or you're willing to accept the ticket and plead guilty/pay the fine being honest usually helps.

If you want to flat out fight it in court, don't admit to anything but don't lie either. The officer will makes notes about what you said to him which can be used in court. Just be nocommital and take the ticket.

You have to decide which of those things you want to do before you say anything to the officer.