Getting
much better. Don't be afraid to brush over the render with some magic / sparkle brushes either. You can also put emphasis on the render by lightening / darkening the area around it. It really attracts attention and makes the background seem less plain. Just like what you did with this one:
The background that is farther away from the render is a different color than the background behind the render, which does attract attention to the render.
Try surrounding the render with something that blends in with the background, or else it looks like you just slapped something onto the background. For example, which one would look better?
or
?
Probably the second version. It looks like that you've done more than just create a background to suit the render. It looks like someone brushed over the render to make it more complex. Basically, I just put brushes over the render and erased some parts of the lower arm. It made the render more than just have the same colors as the background, but it actually has some effects that are similar to the background now. The magic brushes over the render are a perfect example of how a render can be blended even more.
Also, see how the background is more white than the outer borders? It's because I want the render to attract attention. White stands out on black / dark blue, so therefore I used white with light blue overlay to make Haruhi stand out.
...that banner wasn't anything serious though. xD; I just made it for an example.
So yeah, try brushing over the render some more and put more emphasis by alternating colors in the places you want the attention drawn to.