Further to Wildwood's post:
Google's web crawlers are looking for links from popular sites to newly-created sites. For example, if you've just created a website dedicated to your collection of porcelain thimbles, you should contact the site owners of every thimble-collecting website you can find (giving priority to those which are high up in Google's existing rankings) to ask if they'll link to your new site (and, of course, offering a reciprocal link). Also join every thimble-collecting forum you can find and submit a post to announce your new site. (The more links there are to your site, the better are your chances of getting it moved up Google's rankings).
Chris