Jim Zumbo, Craig Boddington, Ron Spomer and Wayne Van Zwoll are all solid contributers to the modern hunting literature. Through their gifts (both hunting and writing) they make us better hunters. Whether it is letting us learn from their mistakes or by teaching us new techniques,they help us harvest more game. But I suggest looking to the oldies, the fathers of the outdoor writing craft, to learn tricks that you might have not used.
I chose to shoot the 270 winchester because I grew up reading every Jack O'Connor piece I could get my hands on. Magazine article, book chapter or biography I would absorb as much hunting knowledge as I could from this wise old wizard of the hunting tradition. Elmer Kieth, Robert Ruark etc are in the same boat. Their stories might be half a century old but they were taking part in the same primal pursuit that we are. The technology might have changed, the equipment might have changed, the sizes of the game populations might be different... but the drive and pursuit is the same.
So hop on ebay and look for some of this old wisdom. You might just end up needing a bigger book shelf!