How do you write a tutorial?

Ok well I am new to the whole writing tutorials thing. And I just made this icon with a coloring effect that I really like. And well I would like to share it. The problem is how do I go about writing a tutorial? I don't even know how to do a "fake cut" properly. >.< Any help would be appreciated.

-- Jane

P.S. If there was a memory for this I must have missed it and I'm sorry