You need to find ways to get back-links from legitimate sites.
There are a number of legitimate routes that your can take, the main one is to create a site which has a lot of good quality content. Users will want to bookmark you and Bloggers will want to link to you.
If you are a Web Designer, after completing a site for a client you can just add site designed by _____________ and your url at the bottom of each page. Most clients will give you permission to do this. This is probably the best way for Web Designers to get back-links.
Specific Engines and Directories
In addition to submitting your site to the major directories Yahoo, Open Directory, Google., research whether or not there are directories for your specific topic or theme.
Blog Directory
Technorati
Focuses on Blogs and allows users to search for blogs with a specific interest.
Shopping Directories
Comparison Shopping Directories allow users to compare prices from different online companies. They charge either a percentage of the any referred sale or a cost-per-click for every user sent to your site from their site.
The following three should still be free, check to make sure: