To adjust the clutch cable:
-no pressure on the clutch pedal (your foot not touching the pedal)
-adjust the clutch cable so that there is a small amount of freeplay (check the factory repair manual for your car; it should be about 1mm; 1/25.4 of an inch)

Note: when the clutch pedal is completely released (your foot not touching the pedal) _and_ the clutch cable is adjusted correctly, there is _no_ tension on the clutch cable which means there is no contact between the fingers of the pressure plate and the throw-out bearing and the clutch is feeling the full clamping power from the pressure plate. (no free play is the same as driving with your foot partially on the clutch pedal)