I have seen many motivational videos, where this question is addressed. Not always, its you who has to see the spark in yourself. Sachin Ramesh Tendulkar liked to be a Cricketer, but the spark was spotted by his brother Ajit, coached by Ramakant Achrekar and Supported by his Father n Family.
Best ways my friend would be to try and fail. Make a list of things that you would like to be or would like to do. Give yourself that time to try everything and pursue all your dreams. Just keep on trying till you get your MOJO. Never stop believing in yourself and don't stop at anything until you have achieved your goals. Don't ever settle for anything lesser than your passion because you work for about 60% of your life. And you want to be happy and doing what you love while you're at it.