Hmm. Maybe this is going to be harder than I thought.
Usually suggesting people lower their freeway speeds is the first bit of advice, but you've already done that.
The next highway technique I'd suggest is "driving with load". Basically - let your speed fall on climbs (constant throttle, if you don't have a ScanGauge), and pick it up again on the descent.
For urban stuff, the biggest gains to be made are in avoiding using the brakes as much as possible (some call it "DWB", or driving without brakes). Coast in neutral when you need to reduce speed, or when approaching stops. If you're comfortable killing the engine when coasting down (PS goes out, PB dies after one or 2 applications), you'll net some good gains there as well.
I'd highly recommend getting a ScanGauge too.
We need to get our motherlist of driving tips posted...