LIGHTNING
Creating lightning is simple and elegant
Create a new image (any size)
Edit your color palette (one dark color, one light color)
Add a cloud filter Filters>Render>Difference Clouds
Add a difference cloud filter Filters>Render>Difference Clouds
CTRL-I to invert the image
CTRL-L to adjust levels
Move the black triangle in the input level grid to desired effect
CTRL-U to adjust Hue and Saturation in order to change lightning color
You can copy and paste the lightning over other images (Blending Mode: Screen to mask the black)