What are you really good at? This maybe your professional area (e.g., design, marketing, or medicine) or an area of your personal interest (e.g., beauty, traveling, or healthy lifestyle).
Of course, it's easier if you have one sphere where you are both passionate and professional. Then you can share your methods, results, and other interesting information right away.
But even if not, it's still possible. Many people around you are doing their first steps in the same area, and you can do it together. You can demonstrate how you learn a topic, show your first results and progress — and over time more and more people will consider you an expert.