I am far from being a pro. What I think you need to focus on is providing a touch more contrast on your effect. The key is to think shadow, base, and highlight on whatever colors you choose. Slowly build up the effect with thin layers.
Don't be afraid to experiment with other colors. If you're worried the blue colors I recommended would get lost on the main color, then change the color set. Try some grays and white, yellows and white, even some greens and white would show up really good against the dark blue. You could go into reds and oranges, but that might take the effect closer to fire than lightning.
Last, make sure to check the articles in the sticky thread under the painting and conversion forum. Tons of good tutorials and articles on varying techniques in there. I don't recall seeing lightning specifically, but then I haven't really been looking. :smile:
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