Honda civic 2000 hatchback with ZC wasting gas?

I have a Honda civic 2000 hatchback and I was wondering what would be recommended to do if it wastes too much gas. Also this car doesn't have a catalytic converter. Any recommendations?Honda civic 2000 hatchback with ZC wasting gas

Do a tune up. Ie filters plugs cap and rotor wires and fuel filter. Put your tires up to spec. Check pressure