1. Make a 400x400 document. Now press "D" on your keyboard to reset the foreground and background colors to black and white. Make sure your background is white.
2. Apply Filter>Render>Clouds. Then apply Filter>Distort>Polar Coordinates:
3. Now go to Image>Adjustments>Invert. Then add Image>Adjustments>Levels:
4. Now add your colors Ctrl+U:
Duplicate the layer. Now set the blending mode to Color Dodge:
There you go, here's my final raging flame effect:
