What realistically can a sub do to change into a better and more obedient sub?

As soon as you add the word realistically in there, I bow out. This is all fantasy, and my experience in BDSM and power exchange relationships is…limited, and the few experiences I’ve had were extremely negative, without going onto gory detail. These stories are fantasy–and I don’t have much practical advice beyond safe, sane and consensual. Go talk to someone like @foxbear–he has written some of the best stuff on BDSM theory and praxis I’ve ever read. I mean, I’m more than happy to fuel your fantasies, but my experience and expertise ends at the imagination.