I don't know what you have had done already, but heres the most common stages:
1. headers/dual exhaust
highrise 4bbl intake/performance carb
ignition(pertronix to start or one of the tuneable setups)
2. cam
heads
bottom end
3. Stroker motor conversion
bored out
balancing, blueprining
supercharger
NOS
Keep in mind this is just engine stuff. Changing rear end gear will drastically change the pull the car has. If you have a 3.00, set up to a 3.25 or 3.50. Also, transmissions can be improved. Manuals can upgrade the clutch stuff for better performance and autos the torque converter and shift kits. Furthermore, keep in mind that the more power you create the more the bottom end of the motor has to hold everything together. Improving the bottom end will make sure that your motor does not eat itself!!!