I would actually say personal branding is not as important early on as niche specialization. For example, you're not just a Rails developer, you're a Rails developer who specializes in building MVPs for SaaS products.
Also I wouldn't focus on content as much right now. It takes a long of time to create and market content that gets meaningful traffic and unless you do keyword research right (or get lucky), it may not even bring in people who need your services.
Instead, you need to ask yourself: where can I find people who need my services? Example: Angellist, accelerator programs, etc. And reach out to them with an idea of what you can help them build. Here's a good template for this: https://artofemails.com/new-clients#developer
Do not wait for them to find you because this is how the feast and famine cycle happens.
There's a flip side to be careful of though. I've known consultants who were probably the world experts in, say, the performance of a now long-dead computer architecture. You do want to specialize to at least some degree. But even if you've found a nice niche, be aware it may not be there forever.
Also I wouldn't focus on content as much right now. It takes a long of time to create and market content that gets meaningful traffic and unless you do keyword research right (or get lucky), it may not even bring in people who need your services.
Instead, you need to ask yourself: where can I find people who need my services? Example: Angellist, accelerator programs, etc. And reach out to them with an idea of what you can help them build. Here's a good template for this: https://artofemails.com/new-clients#developer
Do not wait for them to find you because this is how the feast and famine cycle happens.