Think of links as if they were votes to your page. Search engines are just computers, they can be great read and index pages but currently they do not understand (at least yet) in order to decide the quality of the page, the search engines clear that other sites are linking to it. E.g. If the page A links to page B, and Google currently already positioned to page to as an authoritative page in that sense, this counted as a vote for page B and honors it with a little extra authority. Two important things to remember when it comes to links. First, not all links are equal. A simple link from a page with authority is much more powerful than many links from sites that do not carry enough weight with the search engines.
Secondly, in the anchor text is important. For example, a link such as: click to learn the words Web design webdesign as anchor text, is much more valuable than click here as a link that you can can give you click. The reason for this is that the text in the anchor in the first example is relevant, and helps the page so it can be linked and can position better on that term, while the second example isn’t descriptive (unless you try to position that term here) as I said before, there is much more in the context of SEO, but if you go to build inbound links with the right anchor text already you’ll be in the streets to topple the competition.