I'm so mad, I wrote a nice long CnC then Gimper logged me out... -.-
Anyways, a stock really wouldn't work with this kind of tag.
As said the clipping masks don't look right. I'd do this:
Get a small hard round brush, any color, then brush with the flow, making jagged
lines. Then with the same hard brush (spacing - 1, rate - 90-100) smudge with SHORT QUICK STROKES
make that a clipping mask of any random stock. If it doesn't go with the colors just runa some GM's. The flow isn't bad.
When making your own background, most of the time you will use C4D's (and either smudge or leave them) or an unsized render
of what you're using (and smuge it). This starts out some good effects to work with. Otherwise you would use a stock, which like I said wouldn't look good here. Until you get really good with the basics and more advanced aspects of tag making, forget about text. Most of the time it will make a tag look like crap, like here unfortunately. That shine in her hair doesn't add anything (though it doesn't make it worse either), I'd drop it personally. The smudging in the lower part of the render looks crappy because you probably used a (round soft brush) which will give you a blurry look. Keep up the good work!