Such a common question only for SEO(which type of seo off page work improve keyword ranking?)

I've good post above about SEO Link Building but I haven't seen a recommendation about buying expired domain name which is also happen to be relevant to your niche having good page rank.

If you are into a competitive niche, this advance link building technique works really well. After buying an expired domain name, you can rebuild the site and link it to your main website.

Trust me, this really works and many SEO masters done this technique. Or you can do some reverse engineering to your competition's website and see how they build their backlinks.

I hope this helps...

i like off page work

Offpage Optmization
 

As I had read the latest google algorithm, the best and working strategies for offpage optimization are:

1: Local Business Directories: you should put all the website information such us:
* Phone #
* website email
* exact address with zip code
* Contact details
* unique website summary description

2: Article posting: Post unique article(500+ words) to all Top 15 High Pr Web 2.0 Properties with links in the content 1 directly to money site and the second is to related news for some news.google.com or wickepedia news.

I hope this will help you a lot as I am sharing mine :)..Goodluck!