STEP ONE
Open a new transparent image 300 x 300. Flood fill with white.

STEP TWO
Go to Masks > View Mask. Back to Mask > Load from disk. Choose the mask you want to use. When it's the way you want it (Masks > Invert if you choose) go to Masks > Delete and hit yes when prompted.

STEP THREE
Effects > Plugin Filters > plugin of your choice. Make any adjustments you choose so it looks like you want and apply your plugin.

STEP FOUR
This step is optional: If it's really light, you can duplicate the layer by going to Layers > Duplicate. You can do this until it's the darkness you want. Layers > Merge > Merge Visible.

STEP FIVE
Add bevels, other filters (such as VM Natural Sparkle), whatever you want. Add another layer and flood fill this with the color of your choice. Bring your filled layer to the bottom in the layer palette. Layers > Merge > Merge All (flatten)

STEP SIX
Decorate with tubes or whatever you want.

And you're done :) Here's mine!

Hope you enjoyed this tut and I hope you found it easy.