Some of the stuff in this is pretty Insight specific, but other parts are useful for almost any Honda Hybrid:

http://www.insightcentral.net/KB/faq-efficiency.html

After reading that page & taking its advice, I saw a good 5-10 MPG improvement.

"Speed doesn't have anything to do with mileage. My truck has an overdrive gear for a reason." - Credited to an unnamed Freeper reguarding changing the speed limit back to 55MPH.