1) Quality/authority website - Positive, links from high quality websites are likely to pass more weight
2) Nofollow tag - Negative, link will be ignored if this is used
3) Relevant surrounding text - Positive if the text surrounding your text is relevant to your site.
4) Age of link - Positive, a link's weight can get stronger over time
5) High amount of links on that page - Negative, ideally a page would be more focused around the link to your site.
6) High quality of links on the page - Positive, if the page only links out to quality external websites that's far better than them linking to anyone.
7) Link from relevant website - Positive, the more relevant the site linking out is to your own site the better.
8) Very high percentage of text links using same anchor text - Negative, if a common trend is found by the search engine's where the same anchor text is used for the majority of inbound links to that page it may appear more unnatural than if it was mixed up.
9) Poor position on page - Perhaps not negative but not as positive as if the link was located in a prominent area, bad could be in footer area with good in top content section.

