I've probably wrote this before but this seems to be helping me alot. I drive 30min to an from work. 90% hwy. I was getting some pretty crappy mileage. I've recently tried not to beat on it like a whore and kept my rpm's no higher than 2200rpm at cruise. If you encounter a slight grade so what keep your foot there. You will slow down some sure... but you'll speed back up when you get to a downhill grade or level grade. This has taken my crappy mileage of 20-21mpg combined to almost 27mpg. Alot has to do with your tune as well granted but 80% of it is your right foot and the distance you are driving.
Also try to keep your tires properly inflated.
Just a little tid bit I thought I would share again.
