I found a good blog post about branding, even personal branding, for entrepreneurs, on the Adhere Creative blog: Entrepreneurs: Crafting Your Personal Brand
If I were coaching you I would say to focus on what the author talks about in #3 and #4, which is to become the teacher/instructor. When you do that you are THE EXPERT. Unless you do a really bad job. Otherwise, you will be seen and known as the expert, guru, etc.
Everyone can do this… you should have enough expertise in your field to teach or mentor someone else.
If you can get gigs to speak at conferences, it is as if the conference is endorsing your expertise.
One other thing that I would strongly recommend is to write a book. I had NO idea that I writing the first (well, second) book on LinkedIn would propel my brand, and my business and my career, like it did. I thought it would be a one-time thing with a week or month of hoopla, but here we are, seven years later, and I still get value because of that book I wrote.