Backlinks - which is a link from another site back to yours - bring the life blood to your website: visitors. Without backlinks you will have to rely on paid advertising and other sales techniques. Google sees a backlink as an endoresment of your site, so without them you will struggle with your search rankings.
Before you dig in, think of backlinks as the result of or a reward for a good marketing strategy - not the start of one.
If you'd prefer to get 'free' traffic to your site by virtual of healthy search rankings in Google, read on.