"There's a lot I could have told you, but it's better to just start and fix mistakes as we go so you can actually see. And you're going to have to make mistakes to learn," she informed him without any intentions of being too discouraging, bringing the brush to the jar of thinner again. "The paints will begin to mix together in the brush, which results in faded, brownish tones. Muddy. Light colours like white and yellow are easily overpowered, even a small impurity will make them look dirty. So you want to save the shadows and darker areas for last. That's why you have to paint in layers."
He added way too much paint to the canvas to start, and she distributed it by beginning very quick, rough placement outlines for the surrounding objects even if they were obviously different colours from the vase, grip a bit forceful as she sensed his reluctance toward the method. "It's your first time, so it's going to turn out a sloppy mess anyway. Just... experiment a bit," and with that she stopped leading, although kept her hand on his in order to take over again if needed.
"It saves time, actually. You're not just painting a single object, you're painting an arrangement. It's the least painstaking part of the process, because the outlines don't have to be perfect. They're just there to roughly define where things will be, so objects can remain in correction proportion and position to each other. Then you can build from there." She tried to remember her own lessons with Dorian, making sure to explain things the best she could.