Beyond the common sense suggestions posted to your answer already, you can look into special synthetic engine, transmission and differential case oils. At this level of friction cheating, you're only going to gain a mile per gallon at best.If you have a roof rack or rail system on your CR-V, take them off. Changing the tires you're driving on now could also impact your milage. If you only drive on the street, get a more street friendly tire pattern. It should also be a bit lighter than the all purpose tires you're sporting for light off road use.And take comfort in the fact that most other SUVs are getting far worse milage than you are. 24 miles per gallon on the freeway is a very good figure for a vehicle of this kind.