If you are going with a nonrepresentational work you might invest some time in defining the shapes. If you want them to have form you may consider shading and refining the shapes. Are the shapes beveled or do they have soft curved edges?  If this shape is intended to be flat then what can you do to emphasize importance of the geometry of these shapes?

 

Mostly the gallery has works that give the illusion of form or depth through some form of texture of shading. Your work may be finished however the common requirement here is to have some form of graphic complexity. Minimalism is fine in the art world but most people here wish to see something that will keep their eyes observing.

 

If the shapes are indeed 3D why not define a light source and then try to map the light source onto the contours of your shapes? If it is not a definable shape then maybe try to add something in the way of visual rhythm or define a unique line to your edges?