While creating back links dnt use anchor text if its not necessary, as creating back-links for promotional or advertisement purpose may cause spam, try to share some good information to attract users with back links on article directories, guest posting etc.

We use two numbers to measure whether a link portfolio is natural:

1) Link / Like Ratio (LLR) = Facebook sharing count / backlink count
It is not natural if you have 100 backlinks to a page and not a single social sharing.

A higher LLR indicates a less natural link portfolio. Natural link portfolios usually have a ratio of around 0.1, and unnatural link portfolios usually have the ratio of 4 or higher.

2) keyword Variation Ratio (KVR) = backlink count with exact match / total backlink count. KVR of 0.2 or higher speaks a unnatural link portfolio.

Of course, there're much more factors in search engine rankings.

Try to get links from Guest posts for your keywords.

Why would you need to check is your link natural or what? Why not you just do natural link building?

Analyze Backlinks have a good clutter-free homepage to check back links of your blog. Apart from just entering the website URL, Analyze Backlinks gives you different options like don’t repeat backlinks from same domain, Show links only from homepage, Anchor Text, Total Links, Outbound Links and more. You can opt for any option according to your requirements.

Open Site Explorer is my favorite online backlink checker site. It is worth trying if you want to compare backlinks between two or more domains. This tools work best when you have a paid account of SEOMOZ, though free tool is good enough to get you started for checking backlinks of yours and your competitor.

Link Diagnosis provides you different options while checking backlinks for your blog like you need detailed report or optimized, you want to check backlink for single page or whole website, different kind of outputs and more. One thing you need to remember that Link Diagnosis works best with Firefox.

Thanks for the keywords. I'm off to make a site and outrank you...

OK, calm down....that's a JOKE

I use SEO Spyglass and Majestic SEO. Both are free (up to a point) and provide enough data for my competition analysis.

Sanj.

Nowadays Guest post is the best way to promote you site and also forum posting, blog commenting etc....

Get links from providing content, I mean link bait....

it would look more natural.