The other essential to successful glazing is a thorough knowledge of what results you're going to get when you glaze a color on top of another, how the colors interact with one another. It's something that can only be acquired by hand's on practice until you're internalized the knowledge and it becomes instinctive. (Exactly how is beyond the scope of this article, but basically paint samples, keeping careful notes of what colors you've used.)
This photo shows the initial glaze, and at this stage it's hard to believe that the leaves are going to turn out as beautiful greens. But the choice of initial glaze isn't arbitrary: it's yellow in those parts of the leaves that will ultimately be a the 'brightest' green (warm green), blue in those parts that will ultimately be a 'shadow' (cool green), and red in those parts that will be brown.
