Welcome
spiderbite9001.
If you aren't into modding your car, pretty much all that's left is driving habit changes ... and there's a sticky thread in the 'general' subsection that's pretty comprehensive.
My last 3 tankfuls have averaged over 40mpg ... so you have plenty of room for improvement.
Colorado? How far above sea level? I'm not sure what effect high altitude has on fuel economy ... I know it hurts horsepower.