>Yes giving talks, having a blog, etc. help but they are a medium to long-term play and you have to wait for leads to discover you or be referred to you.

Those things can definitely be part of a strategy and a lot of (but by no means all) successful consultants are known from speaking/blogs/books/etc. But it's also easy to slip into patterns where you're spending a lot of time and at least some amount of money for random generic exposure without any real sales/marketing strategy connected to it.