Working with watercolours is something I never do for clients in the past because it's difficult to amend if revisions are needed. And if there are mistakes (eg. wrong colour), i'd have to start from scratch. Those are common fears I think fellow illustrators have too. Lately, I've been taking on some watercolour projects like this one, to overcome those fears. I'd to redo a few drawings. But so far, it's actually been quite painless. Pencil + watercolours.