To rank highly in organic search results, it's important to earn high quality links relevant to your industry. Like everything worthwhile in life, you cannot create a long-term strategy based upon buying links to your site - instead, you'll want to cultivate relationships with business partners, credible bloggers and publishers as well as other media outlets in your industry to generate links.
While there are short-term strategies that can generate SEO links to your site, the most effective, high value links are generated through building a credible, high quality brand.
By following the golden rule, you should always start any link building campaign by ensuring that your site is high quality. From the content to design of your website, each element should convey a message of authority along with your corporate ethos. If you're a vacation travel company, the look, feel and text of your site should be whimsical and fun, while also providing important information. When you have a site that conveys the proper message, you'll be able to more easily build high value relationships with other site owners.
Always think about building relationships and adding value to your link partners, rather than just emailing to ask for a link exchange. You might want to offer to write a guest article or post for an industry site, or join some authority industry trade groups that offer links. In general, the value of a link is proportional to the difficulty to obtain it - always focus on building quality links that will add long run value to your search rankings within your industry.