When it comes to developing a particular expertise in your lifetime, there's some quick and easy analysis you can perform on your birth chart to determine where yours lies and may improve over the course of your life.
First, as an evolutionary astrology, it's my belief that we are given the charts we come in with not because we're experts in those energies, but because we're here to integrate and learn them. You are growing INTO your sun, you don't arrive with those skills, traits and that wisdom. Which, brings me to the first place you can look for personal expertise:
Enjoy your areas of wisdom, and develop them throughout your life. You'll find much satisfaction in the process!