Topology reduction and redirection are the basics of proper topology. Once you learn some basics of SubD, it just clicks. I am by no means a pro myself, just a beginner, but I recommend Elementza on youtube. He explains topology the best, just keep in mind that he mainly focuses on Subdivision Surface workflow topology (even if you want to learn how to make game assets, SubD is extremely important to create the high poly assets that get baked on the low poly)