Critique my popculture art

[ishbandori]

Hi guys as well as a Mechatronics Engineering Major, I also am trying to break into the art scene on redbubble with some popculture art.

http://www.redbubble.com/people/ishbandori

I don't expect anyone to buy any of the art that I've designed for t-shirts, stickers, Ipads and phone cases but it would be great just to tell me in your opinion what I'm doing wrong.

Thanks in advance.