Hello, I'm an inactive member (I think) in XG. This tutorial should help you out with some different techniques you can apply to your signatures to help with creating flow, lighting, etc.. There are other tutorials on this website that are also good to look at if you find this one either too easy or too hard.
http://www.sigtutorials.com/tutorials/basics/fire-effect-signature-tutorial.html
Thanks Rave!
Love your signatures btw. :3