Man, this reminds me of the times i used to make signatures ... like years ago
anyways this is how to improve it, when making grudge sig's make it 400*100 it just looks good trust me. Also i quite like the colors u and brushes that u ave used but the character brings it down, try using a character like uhmmm i dont know anyways get a nice picture, double the layer blur it then hard light it and blend in the edges.