These are some interesting techniques that I found for successful landscape paintings.
      1.  Redesign your subject whenever necessary
      2.  Look for the dramatic (striking-standout appearance) possibilities of an unusual vantage point
      3.  Include only one center of interest in a painting
      4.  Understand and apply the rules of perspective
      5.  Prevent the viewer's eye from leaving the picture
      6.  Guide the viewer's eye into the painting with directional lines
      7.  When in doubt, simplify your design
      8.  Vary your solution to the same subject
      9.  Occasionally tell a story in your painting
    10.  Simplify areas to accentuate detail
    11.  To bring a painting to life, include a figure
    12.  Choose the best lighting for the subject
    13.  Play lights against darks, not color against color
    14.  Group lights and darks to avoid a spotty painting
    15.  Limit the amount of light in some paintings
    16.  Make the focal point a tonal climax
    17.  Emphasize the dark shadow sides of white buildings
    18.  Utilize the decorative cast shadows of trees
    19.  Make shadow directions consistent
    20.  Paint luminous shadows
    21.  Paint the foreground in shadow for a dramatic lighting
    22.  Dramatize a composition by adding cloud shadows
    23.  Emphasize the foreground by placing the background in cloud shadows
    24.  Achieve tonal harmony by departing from the literal (as written)
    25.  Perceive the colors in white snow
    26.  Achieve harmonous color through restraint
    27.  Create atmospheric distance by the use of color
    28.  Introduce warm colors into a summer painting
    29.  Paint moonlights with more colors than blue
    30.  Observe more colors in water than blue
    31.  Paint cool shadows to make sunshine sparkle
    32.  Perceive the colors in white clouds (to become aware of)
    33.  Make patterns of sunlight on buildings, paint toward the sun
    34.  Exploit (use) wind ripples on water
    35.  Darken the adjacent sky to dramatize a light object
    36.  Choose back lighting for dramatic effects
    37.  Design roads in an interesting way
    38.  Pace horizon above or below the middle of the picture
    39.  Diminish (make smaller) sizes to create greater depth
    40.  Diminish values for a feeling of distance
    41.  Create depth by strengthening foreground detail
    42.  Maintain distance spatial (space) planes
    43.  Try placing the focal point in the distance
    44.  Keep distance water below eye level
    45.  Make tree shapes varied and  interesting
    46.  Relate tree trunks and branches to the whole tree
    47.  Keep the sky lighter on the side of the source of light
    48.  Make skies interesting without competing with the landscape  
    49.  Paint a more dramatic sky than the one actually there
    50.  Vary cloud shapes for a better design