This is a great post. I think your first picture fits your username quite nicely - your smile is almost verging into the crazy - I mean that in a good way :) I consider myself pretty flexible for a 37 year old man (I can easily put both palms flat on the ground in front of me) but I have been battling some tightness in my hip. When I saw a physical therapist and we started discussing what changes had happened in my life I realized that when Thing One was born a few years back I had almost entirely stopped stretching. I used to work out and stretch for about an hour every evening and while I still do body weight exercises, push ups, pull ups, planks, etc., I had pretty much stopped stretching.

Now that I am conscious of this and stretching regularly again it has made a huge difference not just in my hip but also in some soreness that had been cropping up in my knee. I highly recommend stretching and you have some great tips here!

I would add to your tip on following breathing for readying on inhalation and assuming position on exhalation, that I have personally found that staying conscious of breathing deeply and evenly throughout a stretch has made the gains much more noticeable.