You will need basic understanding of how light works around 3D forms. It is important you know how to render basic shapes like a cube, sphere, cylinder, etc because everything can be rendered just by knowing those basics.
To create the color sketch, I use solid brushes first to mask out the flat colors. I only use dark colors for now because I will add in the lighting later on.
Once the basic flat colors are done, I add on the light one at a time. I add in the main light first. This is a directional light so make sure you put proper cast shadows that wrap around the forms. I do this first to get a feel on the final light direction early on.
The next light is the ambient light This should affect everything that the main light does not hit. It goes from top to bottom and is a cooler color for contrast.
Next, I add in the bounce light from below. I made it slightly yellow orange to indicate that the main light is a bit warm like the sun.
Finally, I add in the energy glow effects using a Linear Dodge layer with an outer glow.
By this stage, everything should look close to how the final would look like so make sure you spend time at this stage.