That is a great question, and there is definitely no simple answer to it. Sometimes the only way to find this out is through trial and error - put yourself through situations and in environments (e.g., jobs, volunteering opportunities, projects) where you will see if you either are 1) good at what you are doing or 2) excited about what you are doing.
In order to be competent in an area, you need to have the right skills and have the will. It will take some time to gain experience in that realm and acquire the knowledge that's necessary for it. Along with the right experiences and knowledge, you need motivation and courage to complete a task. So, if you start something new, give it a shot for quite a bit before you acknowledge that it isn't the right path for you.
Sometimes however it's not reasonable to go into a career and test out whether you are talented in that area or not. I would suggest taking personality tests (e.g., the enneagram test) to learn more about yourself. There is also a "strengthsfinder" test that will pick out your top 5 strengths. You should also recognize what your motivators and values are. Based on those factors, you can search for industries or companies or roles that align to it. It's important to start off broad, then narrow it down based on what you go through.
Remember: you as an individual are constantly evolving and changing and so it is always possible to pivot into a completely different direction later in life or go backward. You always want to ensure that you are never unhappy with what you do and you are at least content. It isn't an easy process since we should always be in self-discovery and self-growth, but it's a great question!
That is a very good question. It can be difficult to figure out what your talent is and how you can use it. You should begin with what you like to do and that uses your natural abilities. I would also recommend that if you haven't already, make sure to study subjects that you know nothing about. This can give you new insights into your own talents, ones you may never had known that you had before. In addition, you should try volunteering with organizations. This can expose you to people in different job fields and challenge you to do tasks that you have never done before.
Sometimes it’s hard! What’s important is to always look into things you enjoy doing. If you enjoy reading, perhaps try writing. If you enjoy art, try any forms of that you can find - drawing, painting, animating, knitting, sewing.
Your best talent often comes from what you enjoy - when you enjoy something, you’ll want to work at it more and do it more, which will then make you better with time.
(And sometimes, try something you think you won’t like or be good at, it may surprise you.)
Sit down and process all the things you love to do. Write down the reasons you love to do them. Then see if any of the things you love to do translate to a career. Then do your research on that career. You can even ask friends and family where they see your strengths and weaknesses are. So you can ultimately make the decision.