Funny you should mention that. My degree is in Electrical Engineering, and my PE is in Controls Engineering.
There are many things you could do. The best thing to remember is that Control systems engineering is actually a cross section of many disciplines. The big difference between Controls and Electrical Engineering is that Electrical Engineering is mostly concerned with the steady state behavior, whereas Controls are very concerned with the initial response and settling time.
Industries that employ Control Systems Engineers include the Petrochemical, Pharmaceutical, and many manufacturers. But don't overlook utilities, such as water, electric, gas, and so forth.
If you like telecommunications and controls, consider designing SCADA systems.
I work for a large water and waste-water utility. We have six plants and a distribution SCADA system. On any given day I or someone on our staff may be responsible for selecting appropriate instruments to measure certain processes, tune a PID loop for proper aeration blower responsiveness to dissolved oxygen meters, Create HMI graphics for operators (not so easy), do forensic analysis of incidents, study network performance for PLC use, select valves used for controls...
You have to be good at a lot of different things ranging from regulations for safety, performance, reporting, and so on; process design; disaster recovery; Real Time Embedded systems; Managing people's expectations; Reviewing plans; Answering weird questions from operators at 2 AM (I've done that more times than I'd like to think about); Choosing valves for proper process response...
This is a broad field, it can also potentially be quite deep in places. I think it's a lot of fun.