A few things I'd change is to increase the speed of the effect. If it's a fire, it's a bit strange to have it move so slowly. I'd also adjust the colors, make them less saturated and more varied in its hue if that makes sense. Finally, I'd remove the Outline tech (I think that's what you're using?). It causes a lot of issues for it to just be a small rimlight, I'd save it for more grandious / effect-mandatory features, like eyeglows or statics or something.

That being said, it's not bad for a flame effect, it has potential :D