One way to tell what your kids have an aptitude for is what kinds of advice they listen to eagerly. This probably works for adults too, but not as well, because adults have learned to be diligent about things that bore them.
One listens eagerly to advice only on those matters where one's own protracted serious efforts have proven insufficient in some salient way. And one chooses to devote protracted serious efforts only to those matters one finds irresistibly interesting. Interest is what matters.