I like using traditional mediums such as water based paints when creating demonstrations in color when teaching visual development. This was done at the Academy around 2004 but it could have been earlier. Notice how the first layers are applied transparently and then followed up with heavier applications of opaque pigment. Makes for a nice effect. This is a very simple and fundamental approach which can be utilized in essence when painting digitally.
Now imagine how effective your art can be when you take it to the next level through story. Thinking in a narrative context and including a story aspect to your work will help define and further communicate your concept while building intrigue and enthusiasm.