>>7698499
Try doing just a section and bringing it to the same level of finish as the reference. As for choosing shadows, just darken and hue shift the color in the light. you may need to saturate or desaturate depending on what's around it. Color can get more complicated depending on what you're doing, but keep it simple for now. I'd say you're better off concentrating on your observation skills. Drawing will carry your paintings and painting is just drawing with a bigger brush. Use bigger shapes when painting. When the shapes are placed correctly, you only really have to mess with the edges. Proko and many other youtube channels cover proportions and observational techniques.