If it were mine, I would put another black strip at the top of the three vertical panels, perhaps a little narrower than the one below it. The overall color seems a little dark, is it just the lighting? And the flowers and vase definitely need to be enhanced, they are beautifully done but seem a tad flat, and need to show up more against the background. Can you shade them with thread, or pigma pens or some other means? And one last thing...it seems to be just a little top heavy, perhaps shave a little off the blue top?
If I can figure how to load a pic here, I'll show you what I mean :{