If it is an exciting startup and you don't have much marketing dollars, start a blog, apply to be a HuffPost blogger for the tech section, create a wiki/crunch

If it is an exciting startup and you don't have much marketing dollars, start a blog, apply to be a HuffPost blogger for the tech section, create a wiki/crunch base page, and brand the business online, and then begin reaching out to your favorite tech writers for mentions in their pieces that has to do with the industry your startup is in.