At what stage are you? And are you trying to use the plasma for deposition or etching?
The first important "parameter" is the chamber geometry since it determines the shape of the plasma and therefore the maximum treatable sample size.
Once you have a chamber, the obvious parameters are partial pressures (grain formation in the gas phase vs. growth/etching only on the substrate), power (growth/etching rate), target-substrate/ -electrode distance (homogeneity) and, of course, the substrate temperature.
Unfortunately, these parameters can vary over orders of magnitude for differing chambers, so apart maybe from the temperature you can't transfer them from setup to setup and accurate temperature measurement is also a beast of its own.