Some expert said that you must be careful with link building; some expert said that you must build your massive link building to improve your page rank. But for me, Link building is not scared like a ghost although you must stay in these rules:

link-building-rules

1. Low PR links, For some reason many webmaster do not want PR0 sites linking to their site, Those PR0 sites could be the next PR3 or better than your site. I don’t care what PR they have, as long as their site relevant with my site.
2. Reciprocal links, This is a little bit controversial. Some Guru’s said that you must avoid these but some other Guru’s said no problem. For me, no problem if they need reciprocal links as long as their website seems fair with this. Just make sure they not a link farm or adult website.
3. Use the right anchor text, Your anchor text is your keyword, you must focus with this.
4. Check Your Reciprocal Link Partners’ Websites, Some website play cheated with remove your link in the next month. Make sure you check your partner site every month.
5. Content is the king, Make a good and useful content and you get your link in one way. No need to linking their website because they need your content.