Quality control innovations: Requirements reviews, Test driven development, Agile. Have a read of Software Inspection by Tom Gilb. The exercises at the back of A Discipline for Software Engineering are also very good (although the main book is not that good).

Edit: It is worth understanding "bugs removed per hour". Every quality control "innovation", has a bug removal rate and will improve the end product, or should do. The bug removal rate, is a calculation you can do. ... But I like to learn by doing, so the above exercises helped me understand.