Tune up and basic maintenance. Start off with oil, oil filter, fuel filter, transmission fluid, radiator flush, spark plugs, spark plug wires and distributor cap and rotor.
After that checks out, replace any leaky gaskets, timing belt, water pump, and tensioner. The gaskets can be changed earlier if major, if its a dribble it can wait until everything else is solid. No sense in taking stuff apart if the motors a dud.
Then you can work on suspension issues like shocks, springs, and bushings. Can also include wheel bearings and tie rods.
Basically, you want to replace worn out items before trying to add performance mods. Don't make the mistake of modifying a turd.