practice.
it's the only thing that works. you can know perfectly how to apex a corner, lean the bike, look where you want to go, etc..., but the only thing that will help you get more comfortable with the speed and performance of it is to do it.
for me, the recurring item I have to re-learn or remind myself of, is too look farther up the road. I tend to look at the outside edge and think "don't ride off that" where I should be looking up the road where I want to exit the turn. Once I lift my eyes up, the distance to where I am looking is much greater and therefore the speed feels relatively much lower.