I'll echo sibling's comment about just doing it. Theory only takes you so far, it's important to actually build and experiment, even if it's just in a simulator.

I can recommend Practical Electronics for Inventors as a solid base of projects to experiment with and learn from. If you want to learn how to improve circuits and optimize for specific behaviors, there is a wealth of information in manufacturer application notes. A lot of the protection circuitry used in my article follows advice found in application notes.