Running

This is a big part of the problem, I need to move away from attitude of:

"Run until you puke and then do two more laps"

I'm used to pushing things too far and need to move away from that to sensible training. I have tried to rely on my instinct to do this but find that after a couple of sessions I relax and then subconsciously start pushing myself to go faster / longer then I am right back where I started, I figured setting myself very strict targets that will put me on a much shallower curve will do me good in the long run.

Get a running partner who's less fit than you.