To improve this sig you should learn about Clipping masks.
There should be a tutorial on them in the tutorial section. If not ill try to whip one up.
Anyways to add a bit more to the left sig of the sig just take a spac stock ( Picture) or something with stars and place it on your signature. Then set it on Linear dodge or Lighten or anything you like. Then lower the opacity on it just a tiny bit. That might add a little "pizazz" to it. Once you learn clipping masks then add a few to the left of the sig using splatter brushes or anything you think would go well with the signature.
Lastly if you want to add a bit more flow then take a 9-15 px hard brush and choose any color that suits your signature then draw a few lines in the direction of the flow and then smudge them lightly and lastly set it on linear dodge or any other setting with about 90-95% opacity.