The number one culprit of bad mpg is improper usage of the throttle. Honda screwed up on this one for the CVT version. If the throttle is drive by wire then they could have created a mode that gave optimal fuel efficiency regardless of how hard the user is pressing the throttle. Instead, they didn't and you have to "feather" the throttle.

What you want to do is minimize the number of bars dropped in the active mpg screen. That screen can tell you if you are feathering the throttle or not. If you see the bars go down smoothly... you are doing a great job. If you see the bars drop suddenly... bad job.