That's a great question and one that's certainly given me a good bit of food for thought as a keeper and coach myself. It is probably the aspect of my (limited club level) keeping that is strongest, but even so it's quite hard to express what it is technically that allows this to work well.
I am very keen on strong hands with keepers and fielders, linked in from a strong Z position with a flat back, and head over the (wide, open) catching area (well it should be wide and open but I don't think mine ever quite looks like what I tell the U11s it should look like). This ensures that your weight is on the balls of your feet and sufficiently balanced for the body to not want to rock backwards/give backwards when you take the ball.
It's really difficult to put into words the process that follows in terms of your glovework: I think the easiest way to think about it is to consider the tension on your thumbs, lower palms and wrists when you open the catching area, and just relax that, letting your hands shut almost like a venus fly trap on the ball. At the same time, you're keeping the lower arms pretty strong/tensed, rather than "giving", and shifting your weight almost imperceptibly *towards* the ball and the stumps before it gets to your gloves. This latter weight transfer usually leads to kids closing their gloves too early and the bounce-out: I imagine it's very difficult to separate the relaxation of the carpal tendons (I think) and the sustained tension of the forearms.
I usually use an app like Coach's Eye to record the time delay between ball in gloves and ball to stumps, and set it up as a challenge with a side-by-side split screen between my demo and the player, highlighting catching area and glove direction at the moment of the impact. Definitely possible to make significant improvements as I've seen it in lots of keepers I've coached.