Here are some things to keep in mind as you set out to paint a landscape:
Consider the shape and size of your canvas. Try a few different formats, both horizontal (traditional landscape) and vertical (traditional portrait) formats.
Tone your canvas. When working outside, toning your canvas with a thin wash of ultramarine blue, burnt sienna, or yellow ochre will help minimize glare from the sun and help you lay down your values. If working in the studio, working on a toned canvas can help unify the painting. Pastel painters have the advantage of already working on toned paper
Bring along several canvases or supports if you’re working en plein air. That way, as the light and colours change, you can put one painting aside and start another.
Use a viewfinder. If working outside, a viewfinder will help you crop the
scene and figure out what you want to paint, the format, and how to compose it. If working in the studio from photographs or sketches, you have already cropped the scene and eliminated much unwanted visual information.
Know how to mix greens. This can help you be more efficient and capture the feel of the landscape more intuitively.
Be aware of the direction of the light. It will change quickly, particularly at the golden hours, right around sunrise and sunset. Keep the direction of the light source consistent if you want to make your landscape scene believable.
Think about where you are going to place your horizon line. A low horizon line emphasizes the sky and gives the impression of vast space. A high horizon line emphasizes the foreground, and a horizon line in the middle emphasizes the line between land and sky. Remember the Rule of Thirds
Lay out your larger masses first. Remember to paint what you see (rather than what you think you see) using selective editing in the process. You may know that the green in the middle ground is in reality composed of billions of individual blades of grass, but don’t paint them all! You can add detail later.
Start with a big brush and use it for as long as possible. Save your smaller brushes for selected foreground details.
Simplify by painting the shapes of value that you see. Getting the value correct will give your painting a feeling of depth and space.
Look hard and paint fast. The energy you put into your brushstroke or mark will come through in the painting, giving your painting the vitality and sense of movement that the living landscape merits.
As in any painting, know your subject, and determine what about it is most important to you. Keep that in focus and use it to make your artistic decisions. This will help you create a more successful painting!