Find the Balance
Balancing the various elements of the shot comes to a photographer in one of two ways. Some photographers intuitively understand what makes a balanced composition. It is immediately and instinctively apparent to them as they choose which part of the landscape will fill the frame. However, if you asked them their secret they probably wouldn't know where to begin describing it.
For those fortunate enough it is an innate aesthetic ability. The other ninety percent of photographers, on the other hand, are fully aware of what balance is and does, understanding the techniques involved in balancing the elements of a photograph and are able to use these techniques to produce striking images.
Everything in the composition must have a harmonious relationship with each of its co-existing elements in terms of size, scale, color, texture, light etc.... If two objects or elements stand in stark contrast they will create a battle of opposition that will render the composition confusing. Of course you may want to have the focal point in absolute contrast to draw the eye but you do not want a number of elements in the photograph vying for attention.
Further, be aware of balancing the height of objects. If, for, example, the top of a tree in the foreground is precisely the same height as a building in the mid-ground or the peak of a mountain in the background then the image will flatten and the photograph will suffer.
Light is everything and in landscape photography it can be your greatest asset whilst also being your worst enemy. The intensity of the sun can, to a degree, be controlled by good use of the camera settings and intelligent filter choice. The sun's position and direction is something you can do nothing about except be aware of how this position affects what you see. Remember that the sun provides its best light during the Golden hours (an hour either side of sunrise and sunset).
To avoid images with high contrast try to wait for the sun to be over your shoulder because if the sun is too high or direct there will be a loss of subtle detail and you'll find issues with exposure.
Bearing in mind that different shapes, patterns and lines will work with you or against you to create a compelling composition that holds the eye, remember that as the sun moves, so the landscape will change throughout the day and the angle of light on objects will change too. So, if you have some outcrops or geographical features working in a diagonal path but everything else seems out of step then the likelihood is that at some point during the day the shadows will fall in such a way that they will compliment the shot geometrically.