Here's how to find what folk have written so far.
1. https://www.google.com/search?q=How+can+i+improve+my+Moz+Rank&ie=utf-8&oe=utf-8
2. https://www.google.com/search?q=How+can+i+improve+my+Page+Authority+and+Domain+Authority&ie=utf-8&oe=utf-8
Since there are fine answers already, I suggest you try those.
How can i improve my Moz Rank, Page Authority and Domain Authority for my website Health & Fitness.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic