The only way to discover your strengths is through feedback analysis. Whenever you make a key decision or take a key action, write down what you expect will happen. Nine or 12 months later, compare the actual results with your expectations.
"Kant described a mechanism as a functional unity, in which the parts exist for one another in the performance of a particular function.
An organism, on the other hand, is a functional and structural unity in which the parts exist for and by means of one another in the expression of a particular nature.
This means that the parts of an organism – leaves, roots, flowers, limbs, eyes, heart, brain – are not made independently and then assembled, as in a machine, but arise as a result of interactions within the developing organism."
— Brian Goodwin, How the Leopard Changed His Spots
I once read a good definition of aptitude. Aptitude is how long it takes you to learn something. The idea is that everybody can learn anything, but if it takes you 200 years, you essentially have no aptitude for it. Useful aptitudes are in the <10 years range.
Your first short story takes 10 days to write. The next one 5 days, the next one 2.5 days, the next one 1.25 days. Then 0.625 days, at which point you’re probably hitting raw typing speed limits. In practice, improvement curves have more of a staircase quality to them. Rather than fix the obvious next bottleneck of typing speed (who cares if it took you 3 hours instead of 6 to write a story; the marginal value of more speed is low at that point), you might level up and decide to (say) write stories with better developed characters. Or illustrations. So you’re back at 10 days, but on a new level.
This kind of improvement replaces quantitative improvement (optimization) with qualitative leveling up, or dimensionality increase. Each time you hit diminishing returns, you open up a new front. You’re never on the slow endzone of a learning curve. You self-disrupt before you get stuck.
The interesting thing is, this is not purely a function not of raw prowess or innate talent, but of imagination and taste.