There should be a small lever with a picture of gas tank sign either on the floor on the driver side or possibly on the driver door lower portion. I definitely believe it should be on the driver side floor off on your left side. In my honda, the same lever you pull to release the trunk, you just push it to release the gas tank door, so try that!
You definitely should be able to sit in your driver seat and look down and around that left side area where you are sitting to find it! Don't pry it because you'll damage the door and if the paint starts chipping it may start a rust spot.
If you have an owner's manual look in there and it should tell you where it is at. Or just go to the gas station and have the guy there look for it for you and it shouldn't be hard to find.
Good LUCK!
