My trick to good mpg is to drive SLOW
Actually I don't think I drive slow, just a lot more anticipating traffic. I view the brakes as a fuel dump pedal. I got just over 30 mpg in our Toyota Sienna van on the last tank when I was the only one driving it, my wife averages about 25 mpg.
I bet a lot of the same things apply to gassers or diesel. Oh and keeping the tires at max pressure. I know that some people are really against this, but after driving 55,000 miles I see perfectly even wear on my tires, and when I finally maxed out the van tires I saw an increase from 23 to 25 mpg. It is a bit bumpier, but I think tighter ride as well, to each their own though...
I just have to Get Darell on here now, a friend of mine from CA that has a Rav4 EV and a Prius and charges his Rav4 via solar.