One of the ways that you hear people advising as a means of building links is to start posting in forums and include a link to your site in your signature and, if the forum permits, in your posts whenever possible.
Unfortunately, there are some problems with getting links this way. For one thing, there’s the question of relevance. If you’re trying to build links for a mechanical breakdown insurance site such as www.goodsamesp.com that specializes in Extended Service Plans, then you would want to find forums related to travel, motor homes and such like in order to get the maximum relevance.
The same goes for the text surrounding that link. Whenever possible a link should be within a block of text that is relevant to both the anchor text and the page being linked to. It doesn’t take a whole lot to achieve this and it gives your link more value than just a bare link or url.
The next important point is to avoid spamming the forums with useless “me too” posts. You’re far better off to limit yourself to fewer forums that you can actively take part in. This way you’re less likely to have a forum moderator decide to give you the boot.
For the most part you’ll only have your link in the forum signature. Depending on the context of a particular discussion thread, you can sometimes work you link into the post but only do so if A) the forum in question permits this, and B) it’s somehow relevant to what you’re writing.
The last thing I’ll mention is the first thing you need to check. Are links in the forum Nofollow? If they are, then that forum isn’t going to be useful for links because the search engines aren’t going to follow them. A good easy way to find out if a link is nofollow or not is to get the SearchStatus plugin for Firefox. It has an option you can toggle to highlight nofollow links.
Just copy this code and paste it on your site where you want the link to appear: