K&R is still a really good book that covers pretty much all of the language. Do note that it is very dated, and stylistically you should not try to emulate them

K&R is still a really good book that covers pretty much all of the language. Do note that it is very dated, and stylistically you should not try to emulate them. Looking at a modern C code base (I have heard redis is well structured) would be the best place to learn a modern style.