Search engines rank, what they consider as "important" websites, higher in their result pages. The importance of your website is ***essed using various algorithms of a search engine; prominent aspects being:your page rank and links from higher authority.
You can also deploy creative ways to secure one-way links to your website:

* Offer "Link to this Site" information on your website describing how other websites can link to your website.
* Have very good content on your website for your visitors. These could be in the form of informative articles, tips & tricks, how-to series, advisory information etc. Website owners are happy to link to sites having good, unique content.
* Offer rewards and goodies to sites that link to you. Rewards can be in the form of free e-Books, free software downloads, free trial offers, discounts coupons, online tools, content syndication or other items of interest.
* Offer link backs in exchange for good incoming links, from other non mission-critical online properties or personal pages you may own.