the clouds and book style dont match, I also think you could get a bit more creative with placement, and maybe flip a book the other way so the cover is on the top, give it a bit of variety.
ok, first of all - i don't know how big your design is - but you should really consider the pixelation of your books - both in pages and patterns. i would like to see this design in it's real size, cus this looks like crap, sorry to say it.. also - the upper right books pattern; the colors doesn't match very good in that pattern..
if you want some inspiration for different "wing" positions.
I admire your persistence with this design, especially sticking it out in Appleworks. But you really need to find access to photoshop or illustrator or gimp or SOMETHING that will let you make non-pixel party picture if you're going to submit to threadless.
Alteratively, you can take a step back from this image and really thing of ways to make the pixel thing work FOR you. But I think that would be a lot harder.
Do some sketching, draw out your books, and find a library or computer lab that offers access to a scanner and an image-editing program.
gimme ideas for titles and how to improve the design. please.