My number one tip for marketers seeking to grow their career opportunities is this: specialize. Specialize deeply. I don’t mean “SEO” or “Email marketing,” I mean specialization like “I’m the best link-focused SEO for the mobile gaming world.” Expanding from a specialization (if you so choose) is vastly easier, in my experience, than becoming known for a broad practice. This is equally true for companies as for individuals. Five tidbits of advice
This follow the same advice that Dan Mall lays out in Mastering Freelance - while being a Javascript developer is great, being a Javascript developer for travel sites is far better. It's all about how easily a potential client can determine if you're a good fit or not.