Lanre,
First- I know *nothing* about art. So... grain of salt here, okay?
I was actually surprised by your prices- they seem low to me but remember ^^ Especially the prints- I know they're prints but they're still amazing and it seems like they should cost much more. Low prices can turn people away.
Maybe tweak your tags- sometimes complete phrases are more of a hindrance than help. Maybe try separating some of the phrases to be more simple?
Maybe make better use of your shop announcement for SEO.
I know that it's expensive to ship artwork but maybe build it into the price of your work so that you can offer free shipping?
Amanda's right- you do have really awesome work! The colorful nature of your work might enable you to market toward nursery/children's art? Not sure if you want to go that direction but the right people WILL buy your work.
I am not your target market because I am on a tight budget and buying artwork (while I would LOVE to fill my house with beautiful work), is not an option. And again, I know NOTHING about art so...
But good luck to you! There are ALWAYS things to tweak, even on the best shops!
Cheers,
Nicky :)