fuel economy help

i have 95 civic ex and my fuel economy is really bad 100-150 per tank
what i have done to the car stage 2 clutch, sparks plugs and wires, distributer, timing belt, water pump, fuel filter, radiator, thermostate, thermostate sensor, most of this things i have done recently and when i bought the car the privious owner didn't tell me about the bad milage on the car i got ****** what else can i do the get the mpg back up

Air filter, EGR valve (clean out or replace), also a poor working O2 sensor will destroy your mileage