So here's the walkthrough I promised to you ^-^ This is how I currently work - it's not professional or anything, but I like it. It gives nice effects on proper watercolour paper too. Hope it's to any use for you!
Edit: I'm sorry for the typos - I edited the text again and again while making this and on two parts it seems that the two versions of a sentence got mixed. Of course now that I noticed I don't have the photoshop file anymore. Crap.
Anyways, please note that where I talk about the shade of the hair, I'm mixing YELLOW OCRE into the base yellow, not more yellow. Because yellow in yellow would just not make sense.