Tutorials

Here's a quick look at my painting processes when working with Fantastic believability of light. 

First I start with laying in background colors. For this I chose some teals oranges and purples.
This is an example of the brush I created and am using for this painting with a drastically different color (also constrained to a horizontal axis by holding shift).
In the abstract forms I found a cube! What a fun 3-d shape to start with.
Here I'm implementing something I learned from Marco Bucci, which is if there is a warm light source that your shadow areas should be cool tones (and vice versa). Note that I've added a rim light on the left side of the cube (this will come back later).
Then using opacity at 50%, I sampled back and forth and slowy created gradients of the colors I blocked in earlier. 
This is my favorite process: adding a ground plane. For me this is when the form I'm creating finally breaks that 2 Dimensional illusion and becomes a fantastic scene. 
As you can see I've added some volume in the atmosphere of the painting creating more depth. If you look in the areas where warm and cool light meet (orange and teal side of cube and ground plane in front of cube shadow) I've implemented a style of cinematography learned from the film Area 51. Many shots are composed with warms on one side and cools on the other and the green aliens separate them in the center. So I used green in those areas where warm colors transition to cool. 
I've implemented yet another lesson learned from Jeremy Vickery about Light Energy. When a light source falls off over distance the intensity does not only change but the saturation and hue shift as well. Note the bounced light of cool and warm underneath the cube.
Almost finished, Dice Tsutsumi uses high lights that are small and intense to make the surface of the object more rich. I've also added some glow which creates more volume and depth. With the darker background you can see the rim lights on the left and the one that I added on the right just jump right off the background.

 Note that when you squint (or look from afar) the values and colors do not mix together. They stay distinctly separate. I've also added some rich white dust particles floating in the air to give it a magical feeling. Now this is ready to be displayed in the local coffee shop!