I have a 89 GMC Sierra what should I do to get better gasmilage?

[big man]

2wd, stock tires, short box, crew cab, V6

 

[Teddybearcub]

Drive 55 and below, no quick stops and take offs, clean filters, properly inflated tires, easy on the petal, limited weight, remove tailgate...

 

[bigboro718]

K&n Air Filter

 

[Sam Chicklets]

Have the catalytic converter checked to see if it's plugged.

 

[knuckleheaf27]

try one of those FLUX CAPASATORS.....j/k.... is that '89 a TBI?