The point about having it warm is critical. My mileage can be great on my commutes and such, then drop significantly over a weekend of neighborhood errands. Hypermilers say do errands from the longest distance in, so it has time to warm up for the furthest out, then it's warm when you do the rest of the shorter trips.

Some say they use cruise control pretty much all the time, even for city driving ~30-35 miles per hour. I don't usually do this myself, though I tried it a bit the other day and it might work out (I find it hits the gas at points when I'd be pushing for EV mode myself, and sometimes it tries to accelerate up a hill when I'm going around a blind turn and that makes me a bit uncomfortable!).

My experience says if you can drive to the point when your battery's well-charged, it's great to try to use EV mode as much as you can, coasting, accelerating slowly, easing toward red lights, etc. If your car's warm and in the right state, it should easily flip between gas and EV when you accelerate or take your foot off. In-city it'll be harder to get it charged up.

Someone here advised me that you can kick it to "hybrid mode" (where it freely switches back and forth) by, _after_ the car's fully warm, having it idle at a stop for 5-8 seconds. It really does seem to work pretty reliably, too. That will make a big difference, because when you're burning gas while coasting you're dropping your fuel economy.

In general a very light touch on the pedals makes a big difference. The less you hit them the better, I think. And keep an eye on things like your battery charge, your fuel economy as you drive, and so on, to get a better idea of what works best for you. Don't let your battery run too low though! You do that and it'll start idling and burning gas while you're stopped, which is very inefficient! So when the battery starts getting low, shift a bit more to accelerating with gas and coasting (pulse & glide). When the battery's fully charged you can use electric mode to accelerate when reasonable too, but don't waste battery when it's low or it'll come back and bite you.

Those're my tips, I'm sure there are plenty more around.