A strategy that you should definitely use as part of establishing yourself as an expert, or at least as knowledgeable, is to establish a blog in which you comment on important topics and issues for your industry or profession.
Your profession might be very broad, in which case you could focus on a specific line or specialty area. What intrigues you? What are you interested in learning more about?
You can ultimately turn your blog posts into eBooks and the basis for presentations, further establishing you as an expert or knowledgeable professional.