“…learn to be it’s master and not its slave.” Gosh, they were almost there! It’s = it is. Without the contraction, this sentence would read: “learn to be it is master and not its slave.”
I’m a communications purist, I know, and I’m sure I make my fair share of mistakes. But this one is critical. For all you newsletter writers out there, make sure you’ve got a grammar-checker handy! People will notice. I guarantee you that.