I was finally promoted from my Platinum division to Diamond Rank 5. I lost a couple games and took a plunge to ~25, but I'm not worried so much about rank. It's just nice to see progress. It was a separate goal to get back into Diamond. It seem's that focusing on mechanics is what actually helped me get promoted.
I reached a plateau a while ago and found myself getting frustrated at losing. I have since then taken a different mental approach to improving (rather than winning to get promoted.) It feels awesome to be back on track.
I read a post in SC2 General about "How to Improve in SC2" and really took some of the core ideas to heart-- setting manageable goals is what will help you get better in this game or anything else in life.
Cheers!