The first thing you do is go to the Google search engine and insert the keyword you are targeting. Then browse the first five pages of the search results to see who has gotten top ranking. These are the people who you are competing against. Knowing that, you can start visiting their sites to see if you can find a way to use their popularity to increase your own. The simple way to do that is to go each site and see if they have a blog you can comment on, a discussion forum you can add to, or any other way to get your name in their site, with an appropriate link back to your website, if possible.