I only have a couple things to add:

RR, you mentioned climbing in the drops. I have found that I cannot do that because I feel like my chest isn't open enough and I can't breathe. Of course, I'm sucking air like a freight train when I climb anyway!

Second, when climbing try to keep the top half of your body steady. Many times I see people standing to climb and their whole body is moving up and down - bouncing, so to speak. That movement wastes a lot of energy that could otherwise go into the climb. Try to keep your upper body still and only move the lower half.