I know gas prices are different all across the US, it is $3.69 a gallon here in Upstate NY right now.
There are two easy things you can do to keep your car as fuel efficient as possible- if you drive a tank, there is no help for you! Just kidding of course!
First: Make sure your tires are fully inflated, I don't know why but it helps a lot.
Second: Make sure you get your oil changed when it is due, and if your car has over 50k miles on it make sure you get high mileage oil.
On a side note, my dad sent me an email about how when you use your credit or debit card at the gas pump make sure that you hit clear when you are finished pumping gas. This way the next person who pumps or the people working at the store will not be able to use your credit card for anything. It is amazing the things people will do for money!