How can make best back link?

[motionz]

You can build quality backlinks by off-page seo technique like Guest Blogging, Article Marketing, Forum Posting, Document Sharing, Social Bookmarkings.

The best way to build backlinks now-a-days are guest blogging which is for creating do-follow links and forum posting & blog commenting for creating no-follow links.
You should always maintain a balance between the no-follow and do-follow links.