1. Create your document, I was making a wallpaper so I made it 1024 x 768 pixels.
2. Render some clouds [Filter > Render > Clouds]
3. Hit CTRL + J to duplicate that layer
4. On your newly duplicated layer, render some difference clouds [Filter > Render > Difference Clouds]
5. Set that layer to "Pin Light".
6. Hit Ctrl + E to merge your layers.
7. Now hit Ctrl + J to duplicate the newly merged layer.
8. Here's where you can pick and choose to customize your image. If you want you can save it as a .psd so you can go back and try other methods. Set the layer to any type you want "Overlay, Lighten, Lineary Burn" Any of them will work. Choose whichever one you please.
9. Merge your layers again by hitting CTRL + E
10. There probably is a better technique to this. But for now Well just do it the way Im doing it. Create a new layer.
11. Fill it with whatever color you want. Neons tend to look cool.
12. This is straying from being a tutorial more towards being a guide, but what the heck. Now with your newly chosen color as a fill layer, once again set it to whatever layer type you want. "Soft Light" looks cool. Now if you want, you can change the opacity type as well. Hit CTRL + E to merge your layers.
13. From here your on your own. Theres tons more you can do to custumize your image. Distorting, Stylizing, good luck. The general purpose of this tutorial was to give you a basis of something you can use as a texture or a stock image thats easily custumizable. Good luck!