With a lean burn vehicle, the magic is to stay in lean burn all the time. Since the VX doesn't come with FE instrumentation like the Insight, and you can't connect to it via OBDII, my recommendation would be a MPGuino, and maybe an AFR meter. Driving-with-load (constant throttle versus accelerating uphill) will help maintain lean burn.
As with any vehicle, coasting to stops (preferably engine off), pumping up your tires, adding fuel economy instrumentation are the best for improving fuel economy.
Do you have pictures of your VX?
