Don't believe a word you hear about incoming links, the quality of the link or anything to do with link exchange because the truth is; it doesn't really matter how many links you have to your site and what sites link to you. What does matter is the way the sites link to you and how often new links show up to your site. If you wake up tomorrow and, overnight, 1 million other sites decided to link to you, that would not affect your position in any way (what it may do is hurt your listing because it will look like spam). Here is how links work for you:
If you are a plastic surgeon and another plastic surgery site links to you, that will give you a boost because you are being linked to a site that has some relevance to yours.
If your site sells used network equipment and the link to your site is like this used network equipment that will give you a boost because the link is a search term.
If you acquire new links slowly over the course of time, that will give you a boost because it looks like your site is gaining popularity.
If people link to internal pages of your site, as well as your home page, that will give you a boost because it looks like you have lots of pages of relevant information