The major factor to get better SEPR in SEO including 1. Backlink 2, Keywrods 3. Keyword density 4. metatag 5. Title
I use Traffic Travis (free version) to help me with this. It also tells me what my competitors are doing.
bad backlings and in such large number is always a problem for google they cannot give you good rankings on basis of bad more backlinks so they think that its all spamming make quality backlinks even if low in number