Here is What I do: I optimize a few keywords and revamp content, design, navigation, technical portion of page, anything else, etc. And rank that page better than what it used to be. This way my Client trusts me and do not need proof of any change I propose. Why not do something they can actually see results and save yourself from wrong. I personally read all of them and I still do: NP, Barry, john Mu, SEORoundtable, SEJ, Moz, rankFishkin, etc. Personally I feel there is not much to learn after 2-3 years of learning. Now any thing new you just naturally come up with solution or strategies.