Sure, there are lots of these sorts of "everything you need to know about buying suits," or "X number of rules of men's style," posts all over men's blogosphere. They'll tell you that fit is everything, that gray is the most versatile color, and to never button your bottom button.All of which are true, but I especially like these sorts of guides that go a little further, discussing aspects like weave, patterns, or, once you have your suit, what to do with it in regards to the rest of the stuff you've gotta wear with it, like your tie, topcoat, shoes, and watch.
This "Complete Guide to Suits" from Details magazine is a thorough one, providing lots of tips, ideas, and things to look for other than those that appear on every Pin-able infographic about these days.
You've certainly heard a few of these already, but you're bound to learn something new. Worth a read:
The Complete Guide to Suits: 57 Rules of Style [Details.com]