Better mpg out of 5.8

I have a pretty much stock 5.8/351w in my f250 and would like to get better gas milage.  Im currently getting about 12 or so.  Though I was wondering if anyone has gotten better and how.  I compute an average of 70 miles a day and every bit helps.  Would a new intake, exhaust, injectors,...ect help.   Let me know what you guys think

i don't know why but i always got better mpg out of the older 351w's with carburator set up i bought a 96 f-150 4x4 with 351w and it only got 8mpg needless to say i unloaded it and got me a 94 f-350 4x4 7.3 turbo and get 16mpg and love it . if u live where u can pass inspection u might try changeing to carb setup hope this helps

I am getting about 8 to 10 with my 1994 Fuel Injected 4X4 5.8 running 33's.