It starts with deep customer understanding
You might have done personas or customer avatars before and think it's a bit fluffy and pointless but in our experience they are anything but. Personas will be only ever be as good as the effort and research you put into them and the continual use and management of them. Personas that get filed and not looked at are probably fairly widely off-base (it can happen when not enough team are involved or when there has not been enough expertise in the process). The competitive edge in the market is found in out-thinking your competition and to do that you need the best insight you can get, from data but also from deep customer understanding.