here's a couple tips i've found that work:

1. use cruise control on the freeways. on the hch.ii at least it appears the ima system knows better than i do how to manage things and return great mpg.

2. avoid short trips (<3miles). these trips kill mpg. i went from 48mpg to 54mpg simply. by using my electric scooter to go down to the store.

3. use the gauges. on the ima system, learn how to read the gauges (assist/charge). learn when to let up on the gas to get into ev-only mode and how to coast (no green bars).

4. get a feeling for how much battery power you've got. if you're only down 2 bars, then use that electric motor! try to stay above half charge otherwise the ice will kick on and force a recharge. let off the accelerator early in front of a light to maximize regen. regen energy is (almost) free energy so the more you can capture (and use) the better.

6. if you've got the battery power, use it to accelerate up to speed quickly. generally, i try to accelerate up to 5-8mpg over the speed limit and then let it glide back down to the speed limit. it is surprising how far you can glide.

7. know your route. there's a big hill on the way out to my parents and the speed limit is 50mph. the hill gradually declines on the other side. knowing this, i climb the hill at around 45mph and then let off the accelerator near the crest and glide all the way down (about 2 miles) at 55mph. by the time i get to the bottom, not only has my mpg shot up but i have managed to recharge my battery. if you manage hills like this you can really bump your mpg up and recapture energy for future use. hills are the friend of the hybrid (at least the ima system i've found).

another example, on my way home from my parents house highway 24 gradually climbs and then the other side declines pretty steeply. my exit is right in the middle of the decline. i power up the hill and use as much of my battery charge as possible to assist. then at the top, i coast (managing the gas pedal so as to not recharge). my speed picks up to around 75mph and at around my exit i let the regen kick in full power and it slows me down pretty good. by the time i have exited no only did i make up a bunch of time, my battery is fully charged again and my mpg is much higher.