As with so many things, I’d just start writing. Preferably something with lists or headings in. That way you’ll see how easy (and similar to normal text) it is. Whether you use Drafts, Daring Fireball Web Dingus as a friend of mine does, or some other Markdown processor is up to you.
There’s actually nothing scary about it, it’s much easier than HTML, and so many places take it.