try to obtain abandoned electronics to "dissect"
reverse engineering household electronics and appliances is a good start, just mind the dangers in things like microwave ovens TV sets, smoke detectors, and CD lasers.
alot of what you see is going to look a lot like, some sort of digital electronics, with some analog control sections, and a power supply section.
there are rules for different types of technology regarding the current voltage and noise allowed.
basically you have resistors capacitors inductors
then you have diodes transistors SCRs and other junctions
and then you get into ICS such as analog amplifiers
transducers of all sorts.
then logic and digital electronics such as bus master controllers, or programmable IDEs