Welcome to the site! Sounds like you have a great platform to start from. I wish I could get 39 in my Corolla (working on it
)!
First and foremost, get yourself some sort of MPG gauge, probably an MPGuino. Adjust your driving and you'll see a big increase in FE. This link should help.
100+ Hypermiling Techniques
Check out the 65+ efficiency mods. A lot of them are aerodynamic based, which would really help you get to your goal.
65+ Efficiency Mods
What part of Oklahoma are you from?