Be a (unit-testing) minimalist
Still (2013) a great talk by Sandy Metz on testing, and how to do it right, without getting too theoretical. While this talk is on ruby, and it uses a Rails framework for testing, it really is applicable to any other language (only the syntax will probably be a wee bit shittier ;))
Watch Rails Conf 2013 The Magic Tricks of Testing by Sandi Metz on YouTube
(and while unit-testing is between brackets, in general, being a minimalist when writing code really is a good idea)