To some, it may come more naturally than to others, but learning still takes place. Second, you need practice. The more a gymnast practices the various elements, the more natural his or her execution becomes. Each tumbling pattern or vault becomes cleaner. Third, to become good, you need a coach.
All amateur athletes have coaches, as do the vast majority of professional ones.
You need a coach to be your cheering squad, a force that pushes you to be all that you can be, a voice that calls you back to the basics when you need it. Fourth, every good gymnast puts his or her own twist on standard moves and develops his or her own routine. This sounds a lot like developing a healthy relationship. Couples need an arsenal of skills in order to thrive. Some will need to be learnt.