I was curious , how would I up my mpg ?

My suburban is a 1995 , 1500 with a 350 I believe ...and it has a carburator

I know by experiance with past vehicles that spark plugs , CAI , and a few other things help , but I've never owned a vehicle with a carburetor so what can I do . I currently get about 11 city 15 hwy ...completely stock , new fuel filter brand new stock paper filter and recent oil change ..thanks in advance !