How to raise up my earning percentage (Amazon)

My earning percentage is 4% as my affiliate board states, what is the best way to raise that percentage which makes Amazon pays me more, is there any easy way? Thanks.

Are you talking about the precentage they pay you per sale? If so it just goes up with the more sales you have, it should say on your main report page something like:

Referral Rate (Increase this to 10.00% by referring 3 more items)

There isn't really a quick way around it besides just selling a whole bunch of items.