Reading material.....can't blame a guy for wanting to read up on the topic.
So....I have a loaner book from a friend and it covers a heck of a lot of the basics and advanced subjects. It was written by Major John Plater, USAR, (retired). The title is The Ultimate Sniper. Don't let the title fool you....the topics covered work equally well for shooting deer, hogs, and elk too. Lots of info about marksmanship basics, breathing, sight picture, reading the wind, bullets and caliber choice, ballistics, optics, etc.
I'm sure others will jump in with other good references for you too.