How to Make an old car more fuel efficient?

I have a 76 ford torino how can i get better fuel economy?

First of all, make sure the engine is in good condition. Completely rebuilding it with every seal and wear-part replaced (with new, if possible) would be the ideal.

Barring that:
Run some engine cleaning chemicals (like Sea Foam) through the crank case, the fuel tank, and the carburetor.

Make sure all filters (air, fuel, oil, and whatever else you have) are clean.

Make sure your carburetor (I presume it has a carburetor… If it's fuel-injected, this could be a lot more difficult) is in tune. If it's putting in too much fuel, you're just wasting it (and probably not running as well as you should), if it's putting in too little, you could be damaging your engine, and you're not getting the power/torque you should be getting (which is important for the one most important thing to do).

Make sure your transmission is in good shape. If there are metal shavings floating around in your transmission or something, or if you've got a bad clutch or something, that could be wasting fuel right there.

And finally, the single most certain-to-work thing you can do: Get a higher-ratio differential. Usually just referred to as "gears." This will for 100 percent certain improve your fuel economy. It means the engine has to turn less for the wheels to turn at a particular speed. What it also means is that you will have poorer acceleration.

Similar effects can be had with different transmission gear ratios, without neccesarily having poor acceleration. The Corvette, for example, has a relatively high 6th gear, which lets it get around 30 mpg on the highway, while the lower gears are lower and closer together so it can blast its way up to speed (while churning through gas like it's going out of style… Oh, wait, I think it is!). But that's a much more expensive proposition than replacing the differential gears.***:D