I've been working on some materials for the Watercolor Workshop this summer and made this painting of a beautiful Heliconia flower, aka Lobster Claw. I painted it as an example of Wet-on-Dry glazes. That is, the paper is dry, not pre-wetted, so the paint tends to hug the paper, stays pretty much right where you place it.
If you take a close look at portions of the painting, you can see the layered glazes. I worked from a lighter glaze first, which is typical for watercolor work, then let them dry. I often have to work on several paintings at one time, putting one aside to dry and working on another until I reach a similar stage.
Looking closely, you can see which layers were placed first, such as the pale yellow and very pale green. These were followed up with the deeper orange, then the red, for the flower itself. Likewise with the greens -- stronger and deeper greens were glazed over teh initial pale layers.