Things I did to vastly improve my idle to super smooth from very rough:

#1. Replace all vacuum hoses, elbows. and connectors.
#2. Replace 02 Sensor if you haven't. Was most critical for me.
#3. Replace water temp sensor/air intake temp sensor (if you have one).
#4. Go to Autozone and get some $1.99 Autolite Copper plugs and install.
#5. Replace OVP if you haven't already or test with a known good one.
#5. Check the hoses going to and from the Idle Air Control Valve. One of
mine was cracked and causing most of the rough idle I later figured.
#6. Clean your Idle Air Control Valve out and make sure it's clicking when
you start your car by leaving it up on top and turning key on and off.
Should be able to hear it operate and clank one way or the other.
#7. Change out plug wires, rotor, distributor cap, and coil.

After I did that, I adjusted my air/idle mixture CCW a quarter of a turn (wait about 30 seconds after you do it each time for computer to adjust) until it started gaging a little and then I backed it up 1/8 th. I would also put my car in drive, put on emergency brake, and adjust air/mixture, until it idled best it could. Last night, I just put in a new fuel accumulator to help the starts and so far ithas started on first crank like a new car would.

Hope that helps.

Steve