[Critique] Any Advice On How to get approved for INPRNT

Hello, I got my first sale on shopify and I noticed that the shipping price from America to Canada is exorbitant. I planned to use Shopify to hold me down until I get approved by INPRNT, but just this morning, I got rejected for the 6th time. I was hoping I could get advice on what my work possibly needs to be approved and what I need to work on as an improvement.

Aside from having the absurd confidence needed to become someone who makes a living from their work, I think my works are only about halfway to my desired artistic goals, so I understand not getting selected, but I want to know if I'm missing anything specific. Please help critique my art.

Here is my ArtStation: https://astrokloud.artstation.com/