If I had to simplify this to one answer it would be this: learning to see! And this is a big topic!
Before it is possible to paint accurately, it is crucial to look long and carefully. This practice takes time and is in fact, a life-long one. Most of us have been trained to connect our visual experience with words. While this is great for speaking and writing, it really gets in the way of communicating visually.
Taking the time to really look at the information that is entering our mind through our eyes and recognizing it as shapes of light and dark is the first step in translating it onto paper or canvas. Intentionally focusing on the shapes of what we see allows us to break away from the need to draw with lines, an approach that is too closely associated with verbal object identification to be useful for painting. Once we can see the shape, it can be placed on the canvas exactly as that shape: see the shape, place the shape on the surface!
Sounds simple! And it is with some practice! And one big benefit of this practice? The experience of awe. It really is an awesome world!
Perhaps better than reading all this, take a look at some of the my time-lapse videos like this one: Ashley