Go outside for starters. What exactly are you looking for here? A formula? For what cartoon? Realism? What have you tried so far? How many studies did you do from the pic you posted? What did you learn from it? Did you try changing the time of day/whether in the pic you posted? Why not?
"What do I need to learn to be ble to play with X like this?"
Fundies then a whole load of effort. Then maybe, it's up to you. No one can teach you how to paint, people can only point out where you fucked up. If you posted your study maybe one of here could help, but other wise you'll get some theory without knowing if you're doing it right or wrong.
