I sketched it first out with a blue pencil then drew the yellow, brown and purple ink lines. Then I put down a few dots of masking fluid for the "sparkles", applied all the watercolours and afterwards put down few more tiny dots of white ink. Oh and of course had to let it dry between each step.
There's a lot of really good tutorials here on dA too but I think the main key to watercolours vs. digital is patience and being more organised in your head. With digital you can go back, undo, change filters and other things around, have layers etc... with watercolours you have to kind of see the finished piece in your head and move gradually from light colours to dark. You can undo and cover up mistakes but only so much. And you have to let stuff dry when necessary. I usually take a whole evening to paint a picture, sometimes two, just because I do it inbetween chores and other things. Paint a bit, go wash dishes, paint a bit, watch the news, paint a bit, oh look the baby woke up, paint a bit... etc. It works out better for me than digital, I don't feel bad taking breaks from a drawing because it's the drawing that wants me to take a break. On the other hand when you do have all your time to dedicate to a drawing then bless the hairdryer!