Without question, the #1 thing you can do to become a process control guru is: Get to Know the Process. The people with the best understanding of the process will be the ones who can better automate and control it. All the controls knowledge in the world is useless if you don’t have process knowledge.
How do you develop this knowledge? Start by getting your hands on all of the documentation you can find. At a minimum, try to get Process Flow Diagrams (PFDs) and Process & Instrumentation Diagrams (P&IDs). You should also try to get operations manuals, equipment specs, and standard operating procedures, if they exist. Study each of these documents, starting with the PFD. Trace the product flow through the process. Identify the by-product streams. Get a rough idea of the size and cost of each material and energy stream.
Next, find a good coach, mentor, advisor, or otherwise knowledgeable person. An experienced operator can provide tremendous insight. Start asking questions. Spend time on-shifts with the operator, and, if you are allowed, operate the process. Make sure you understand every step in the operation.
The drawings will tell how the process is supposed to behave under normal conditions. The operator will tell you about all of the abnormal situations that can occur. You need to understand both to become a process control guru.