while doing the basic maintanence should help, i think the biggest problem is that your only going 10 miles. thats not long enough for the car to really get warmed up and on cold days the car may never even go to closed loop.
before my dad gave me the zetec (about 3+ years ago now) he used to get almost 40MPG :shocked:. he works in Cincinatti and we live down by Louisville so it was about 2 hours of all highway all the time. once i started driving it to school (about 5 miles) i was lucky to even get 30MPG (its an MTX so that helped alot).
FWIW i still get about 28MPG with the turbo on the zetec. at least when it was running