I pled not guilty to ticket for moving violation on NJ Parkway. What do I tell judge?

A NJ trooper wrote me a ticket for unsafe lane change (failure to use turn signal) on the NJ turnpike near Woodbridge. I believe I did use my turn signal, but I'm worried that it's just my word against the trooper's. I have already pleaded 'not guilty', and I'm just waiting for my court date. What should I say to the judge? I don't have any moving violations (or parking violations for that matter) on my record. Also, I live in New York City (but I can easily reach the court house by train).