EGO spoils everything, literally everything.
The more we let it to grown in ourselves, the more damage it does.
On the steps you mentioned, I think that the first two are most crucial to deal with our ego, hearing someone else's point of view won't cost us anything, maybe we have a good proposal but what the harm in embracing a better one if available. There are many times when I have seen better opinions than I haven't expected and they did yield better results too.
Well, the last point of yours, to learn to say NO to things which I don't agree with is the place where I lack miserably. Often there are things that I should have avoided for my self-interest but I end up doing and later I regret not denying them.
Btw well written, it was a good read.