The sig look pretty good already. I'd suggest lowering the renders on the image and u should add something to fill up the white space on the sides.
I felt it sould have something on the left hand side as it looked empty and a waste of space (something like colourful clean lines would look great there I think).
I'm loving the emptiness in this. The focal clearly shows out. And the colors are for my pleasing. I'm loving this misty. For your text, it should've been going the same direction as those fx are. To add a bit more detail for the bg, add a soft brush and just go a little around the place. Set their mode to something that doesn't show too much, but is easy and covers space. Overall, I'm loving this one, GJ ^^