Bill Brody said something really interesting about making a landscape painting. He described two kinds of looking : with the edges of our eyes (peripheral vision), and with the centre of our gaze, which is called foveal vision.
I had to look that up too. But it's self evident to anybody who spends time looking or drawing. The centre of your gaze is sharp and log-jammed with detail while the edges are only interested in big differences of form or light or movement. Centre vision evolved for hunting, edge vision is for detecting predators. I like to use both when I am drawing, screwing up my eyes so my centre vision goes fuzzy. My friend Nigel said something wonderful about assessing a painting when you go into the studio in the morning .. "You sneak up on it and look at it out of the corner of your eye". Bill Brody was talking about how painting lets you direct the viewer's gaze by modulating descriptive detail, colour and tonality. This connects with the Italian word caminare, walking. You can be walked through a picture by colour cues - brown = foreground, through green to blue = distance. Can do this with tonality as well.
To me this is exactly what the drawn gesture is, it's a visual invitation to pay attention. I have the most trouble with the opposite though, with flat areas of tone. They often end up as just that, flat, laying over and obscuring the bones of the drawing. I REALLY want to get back into the studio .. I just need to get all the builders stuff out first :-((