Ask HN: Advice on building a brand as a freelance developer?

I have been working as a freelance developer for a few years now. All my customers come through a middle-man, typically a consultancy agency.

I believe I am good at what I do but I dont have any strong brand per say.

What would you do to attract better clients and get a higher rate?

Any thoughts on things like starting a blog, being a conference speaker, or working on an open-source projects?