First place a number of related links on your site, then contact those sites asking for a reciprocal link. You'd be surprised how many people are willing to do this. Once you are in an engine, check your site at least once a week. Strange things happen. Pages disappear from catalogs.
Links go screwy.
Watch for trouble, and resubmit if you spot it. The engines have grown smart enough to realize some sites only change content once or twice a year, so they don't visit regularly. Resubmitting every month or two will ensure that your site's content is kept current. Some search engines take weeks or months before they update their catalogs. For example, WebCrawler's catalog has been as much as 2 - 3 months behind.