Did you follow that youtube tut that you posted in a thread a couple days ago? If so, bleh. That tut was crap, the guy making it even said as much himself. Duplicate render + gaussian blur is a very bad way to make a background, IMO.
Try smudging, but not the type you're doing - use some scatter and shape dynamics etc., and use a nice brush (chalk brushes, splatter, etc.) instead of a round one (you can use round, but I prefer the smudging effect you get with a different type of brush).
Plain color backgrounds also work as well, depending on the sig.
For font, stick to simple things (like I see you've done
) like Arial Black, Arial, Times New Roman etc. etc. Try to make them not so visible, make them blend in more by using a more subtle color and size, also position the text in a good place so that it looks nice. Varying the color on different parts of the text is a nice effect as well (like Mateo113 be one color and then MFN be a slightly different shade, or whatever).