LINK BUILDING
1) the "relevance" of your website's content to the term or phrase that is being searched on.
2) the "interest" that other websites show yours (the number and quality of links to your website). One most commonly used method of building incoming links these days is article creation and distribution.
The amount of quality links there are pointing to your website directly effects your positions in the search engines.
A focussed link building campaign is extremely benificial. This can include such things as directory submissions, article and press release syndication and social bookmarking.