Just wanted to share a small success: I just averaged 27 mpg for an entire tank worth of mixed driving (340 mi). So not bad, as it's 42% over EPA estimated combined mileage for my car.
I call it "small" because it's not really one of my milestones (first on the list being sustained > 30 mpg highway), but it is a significant mark because I've worked pretty hard for it. Ironically, the improvement came more from my city driving than from highway, but it still had enough of an affect on the tank to push me over the 27 mpg mark.