Dear Sister,
Plant commissioning is a vast field and includes different parameters. First of all, if you explain the type of plant then it would be easy for me to advise you best of my knowledge as it varies from plant to plant.
But the very basic thing is the understanding of Plant drawings specially ISO drawings through which you understand well about whole process. Secondly, you may have a strong knowledge of the plant process to be commissioned.
Again, if you provide me details of the plant to be commissioned, i would be in a better position to guide you well.
Waiting for your responce.
Regards,
M. Sohail Rana