The activity of getting sites to link to you can be explicit and formal:
E.g. the request: "your site is awesome, will you link to ours?"

Or it can be a natural extension of providing good content. If a blogger or webmaster deems your content useful enough they'll reference it to reinforce a point:
E.g. "For a legal discussion on linking read this.

The first option requires repeated effort on your part, and has a disproportionate return for that effort. The second option requires you to create interesting and useful content that others will naturally refer to. Getting people to talk about your content in this context means encouraging them to post links to it on their site, or through del.icio.us, Digg et-al.

Q: How do you encourage people to link your content?
A: By any ethical means possible!

Making linking to you worthwhile is called link baiting, and if you have no idea how to go about that you shouldn't be writing at all- in fact you shouldn't be allowed near the Web. If you think that what you write is unlikely to draw any attention you should give up and lie down quietly in a corner, maybe stop breathing too...