1. Relevancy always before PR for except for one exception. If a site is an authority I.E. latimes.com then these are absolutely to be considered. Each potential paid link needs to be evaluated using google pr, alexa rating, backlinks, sites indexed and the value of content.
2. Where will the link be placed on the site. Preferably on the very top of the page and looses value the farther the link is down on the page.
3. Very anchor text per link… VERY IMPORTANT
4. Make sure all incoming links for a site are going to the same location i.e. WWW or no WWW
5. Link to home page and important sub domains as to look natural.
6. Don’t buy to many site wide links on unrelated sites
7. Don’t Farm your I.P.’s . Buy links from sites that are on different I.P. networks. I.E. if you find a site that has 5 other sites that they might consider linking back to you. Check there I.P. of each site to determine if they are farmed or on separate I.P’s.
8. Buy links from a range of PR’s so it looks natural.
9. Watch the outbound links from potential link partners. To many could devalue your link. Buying links from a site that limits it’s advertisers to around 15 could be possible good link partners.
10. when buying links make sure they are not redirecting
11. link should not be surrounded by java script
12. offer pre-sale pages or content for a link- you give them content they give you a link within that content.
13, check the age of site archive.org
14. the number of pages indexed in all SE’s is important.
15. The better number Quality of backlinks increases our PR.