You need to narrow that down. For example, what sort of system do you want the micro to control (or did you mean how to control a micro)?
What aspects of control particularly interest you? Coding, electro-mechanical, industrial, robotic, ... ?
What aspects of electronics interest you? IC manufacture/design, discrete components, high frequency, audio, .... ?
If you have a particular career path in mind how are control/electronics used by organisations you might wish to employ you?
What experience/skills do you have in the relevant fields?