This is one of the best link buidling requirements list I’ve ever seen. If you are having a company or individual build links have them follow these rules. Most importantly, have them report the links they’ve built for you.
There are a lot of shady tricks out there and this list will help you avoid 99.9% of them.
GUIDELINES
1- One link per domain. No more than 3 links from the same Class-C IP address
2- Require One-way links only
3- Links should contain the target keyword/keyword phrase (we will supply the target keyword/keyword phrase) as text in the link anchor text hyperlink
4- Links must be permanent
5- Links must be in text, no graphics
6- Links cannot be from framed pages
7- Links cannot be through a JavaScript
8- Links cannot be through a redirect script
9- Links cannot be on Flash sites or pages
10- Links cannot include a rel=nofollow tag
11- No links using any automated techniques or black-grey hat techniques of blog comment spam, referrer spam or ANY other shady tactic.
12- Page containing link must not be excluded by robots.txt and the anchor text must not contain the rel=nofollow tag.
13- Linked sites must be in production and active . (Developed and not under construction).
14- No sites that require payments
15- No Scraped content, mirror sites, link schemes and sites overrun with contextual ads, popups, intrusive advertising, etc.
16- No link from: guestbook’s, social bookmarking, classifieds, dynamic links, link farms, link-exchange programs, forums, directories, articles submission, Free For All websites, hacker, pharmacy, illegal, pornographic or generally black hat sites.
18- Links must be manually submitted ONLY. No use of Automated software (e.g., Zeus, Arelis or others
19- We reserve the right to cancel any link if not found suitable.
20- Page containing link must be reacheable using normal flow navigation from home page and sitemap (if present)
21- Link page should be from English / German / French language sites only
22- Link page must already be indexed and cached by Google within last 30 days.
23- Links must be on pages with 20 outbound links at most.
24- Links should not be listed, illegal and other offensive websites (porn, gambling, spam, ban, or blacklisted).
This is a short list of how to SEO. There are many many more factors that effect your rankings but these are the proven techniques. Due to the high amount of speculation there are many things that may or may not work. These however, are accepted industry-wide as standand SEO practices.