"This is an easy exercise of how we can create a whole imaginative world starting from illusative sketches and shapes. So we start in a new file, just start to draw some lines and curves and shapes using brushes in different opacities and sizes. Try to pull out some dark and light places. Its more easy to draw in many layers because the next step is to apply some effects in these layers (overlay, colour dodge, multiply, color etc) and capture the screen that we like more maybe because we can see some shapes come out.I give the screen i choosed to start with..