I tend to drive slower than most. I stick to the right lane and go around 57 or so. That's the sweet spot on freeways I have found. I'm also quite a stickler for my mileage and do all the right things to eek out as much as I can.

One thing I have found helps is when going down hills, I actually accelerate a little since that's when I can afford it (just enough that I feel it, but not enough to make the MPG bars go down much at all). That gives me a momentum boost when the hill is over, and then I just coast along.