What can be best off site strategies?

I am looking for best off-site strategies for longtime but still now I didn't find any useful informations. For this search, I have read many article from baclinko, moz and many authority sites but I didn't find which can help me. Everyone suggesting guest posting and High-quality sites. But they are not mentioning any site name. SO please please someone help me to learn more about this.

Thank you very much for reading this.

Poster :
Mazid Chowdhury