I'm just beginning too... : )
What I've discovered so far:
You can move stuff around in the editor (those triangles) but it doesn't help much if the original flame isn't good. It's annoying you can't see what the flames in each batch look like, and it's probably better to work with twenty in one batch, program might react faster.
With the mutations you get 8 new ones each time. 'Speed' increases the amount of mutation you get. So I find a decent one at high 'speed', then lower the speed to make incremental changes till I get one I like. I use low quality so it doesn't take so long to render. If it looks good I up the quality. Then I save the parameters in case I want to work with it again in the future if I actually begin to understand what I'm doing. If it's really good I render it on as high quality as I can, otherwise I just go 'full screen' and take a screen shot of it. : )
It does help though if you start with a decent original flame - download from internet. I'm about to post a pic I made with one. It looks cool from the beginning, and if you are nice to it it stays cool - being nice = not mutating it much, and instead using a 'script' to change it. It's very unclear what each one does, but some of them play in a little animation window and when you press stop you get the flame at the point in the animation which you saw.
You can get gradient packs from the internet as well to boost the amount of colours + mess with the gradients, change backgrounds, move the camera, zoom in. Zooming in to high detail takes forever to render. The blue one above took about 1.5 hours to render for example, should have just taken a screenie : ))
I look forward to seeing some pics from you guys, matt, eno, machineman, maybe Shane too...

and anyone else who wants to 'play'! I have a feeling I'm about to get pwned ;D
On my way to post the next bunch...
Krigl