K, did a small example, pretty basic and not that good, but I'll explain a few things I started with your sig. I use GIMP with all default stuff. Basically, I used flame renders (filters>render>nature (I think)>flame). I used them on dodge layers and burn layers. Then I used some brushes to blend the bottom of the render, brushed on a value layer at low opacity. After that, I played around with color balance, contrast, lightness and saturation. I also erased abit the layers on top of the render so some of the basic colors stayed. I'm a beginner at this (this is my 5th one I think), so all I do is more by instinct than by experience. So just play around with stuff, don't be afraid to try. Hope that helps, pm me if you're not sure about some stuff.