As SEO is the game of links and more links and SEO professionals can read the mind of Google and make strategies by understanding its algorithms.
To avoid penalizing from Google, getting more benefits from link purchasing, the following steps need to be followed for link building campaign.
Links from TLD Sites
Links from top listed domains (TLD, .com .net .org) considered as quality links. But remember domain and content should be relevant to your links and relevancy should seem to be natural.
As Google give much weight-age to older domains. With other points this one cannot be neglected.
PR and Alexa
Before going to finalize the deal, just check the page rank and alexa of the domain as well as the post with Google page rank checker.
IP and Server Location
In case of purchasing links from two domains, make sure the IP’s should be different, at least c class and these located in different server locations. So you could get much juice from Google rather than increasing the number with less benefit.
Referring Domains and Backlinks
With authenticated backlink checker tool, check the number of referring domains and backlinks. Referring domains should not be minimum and same case with baclinks. Historic and fresh should be viewed.
Home page, site-wide and footer links did not meet the relevancy criteria. Hence, these types of links can be traced out easily. Links within content are fine with Google as Google algorithms cannot filter these. Links have much value in the eyes of the Google which are at the start of the post.
Domain Authority and Page Authority
These days there are some ways to get PR with programming skills even with fewer backlinks. To verify and get in-depth for quality purpose, domain and page authority should be above fifty with maximum and quality backlinks.
If the links are no-follow then it is just wastage of money with no such other benefits. Links should be do-follow and it can be checked with any toolbar or by exploring the page source. This type of code will be there in page source. (rel=nofollow)
By following these steps while purchasing links from high PR sites, you can obtain maximum benefits in shape of PR and keyword ranking. Avoid penalizing from Google and acquiring many benefits from link purchasing campaign is the ultimate objective.