I recently went on a painting trip to Teton National Park in Wyoming and spent about 12 days painting. Its very easy to get caught up trying to paint details of subtle stuff, especially if its a new area. The details catch our eye and we become enamored with small things that seem different and interesting to paint. I think were naturally drawn to detail so we have to train ourselves to think abstractly in terms of shapes Below is a 16 x 20 that I did in the park. Its a little larger then I usually work so I went back for a second sitting to finish. Develop your skill as a Plein Air painter and check out my online course "Plein Air Painting Course".
When I look for subject matter I try to eliminate details and see the subject in shapes of values and planes and this is how I'm trying to see the subject, void of detail a bit more on the abstract side. Its easier to simplify this way. Squinting your eyes when looking at the subject helps to eliminate detail.
Here is another Teton painting, 11x14. The mountains, trees and foreground where full of detail and I had to see past that for three quarters of the painting. Most of the painting is spent trying to get the value and color relationships right between the large dark and light shapes.
So this is how I'm trying to see the landscape, simplified shape and value. It takes an effort to see past the unimportant stuff but after a while it becomes second nature to visualize the shapes minus the detail.
It helps to start small when painting outside, 6x8, 8x10, You don't have a large area to try and cover in a short time and you don't have any room for unnecessary detail.