If you want to achieve success in any online business, you should treat it as a normal business.
And what is most important thing in normal business apart that you have good product or service? It is definitely marketing.
Same thing is with online business.
You cannot expect for your online business to be successful if you build a cool web site and than wait for customers to come.
That is not going to happen.
You have to promote your web site.
Best way to promote your site is through search engines(SE) like Google, Yahoo or Bing.
If you want to achieve high rank for your web page in search engines rankings, you should first optimize your web site for SE.
Then, you need to build as many links from other web pages on the internet that are pointing to your web site.
That is called backlinking.
Google and other SE like Yahoo or Bing count this inbound links as votes for your web page.
So, if you have more votes that means that your site will have higher position in SE results.
Of course, not all links are counted the same in the eyes of SE.
If your inbound links are coming from authority sites that have quality and unique content and they are related to your site, they will have more importance for SE.
And, on the other hand, if your backlinks are coming from spam sites, not only that they will not be counted as important votes for your web page but even can damage position of your web page in SE rank.