You distinguish yourself from the sea of competitors by creating great content. I'm not joking either. Creating high quality, highly relevant, engaging and SEO enhanced content is arguably the most important marketing exercise you can undertake. It takes a while for your content to be indexed by Google, but once it is the effects are cumulative (the more content you add, the more traffic you generate) and persistent (unlike online advertising, which offers no long term benefits).
Less than 5% of all purely online businesses (i.e. business that have no traditional, physical counterpart) ever actually make any money. It's hard to draw a decent living from the Internet, but because it is easy to setup, the allure is great enough to keep people trying. If you are to be successful it is imperative that you avoid the mistake of not being disciplined in your approach.