How do you create spritesheets?

[Silverthorn]

I don't want to know how you create single sprites or any tutorial, I just want to know if you have any kind of organization when making spritesheets. For example: do you put each element on a different layer? Do you just draw one sprite on each layer? Do you have a clothes-layer, a skin-layer, etc? Or maybe a totally different strategy? Tell me how you manage your sprites!