...Two more thoughts:
(1) You might try everything folks have recommended and still not see good results right away. I got 23 mpg on my first tank and no better than 27 mpg for the first two or three months. Now I'm almost always 30-33 mpg.
(2) The hybrid system does not necessarily behave the same way under the same conditions from day to day. Some days the mileage can really suck. I'm convinced -- but this is speculation only -- that there are battery reconditioning algorithms, or some other type of periodic adjustment, built into the computer. You'll have a day now and then where the hybrid system seems hardly to be working at all, and other days where you are marveling at the fact that you are motoring uphill at close to 30 miles per hour on EV only. Go figure.