Look at three images below. First image. On it very sharp transition between the sky, the earth and a shed. Here the place is simply left.
This second image. It is much better as tone of the sky is added.
The third image includes the tinted sky and clouds. Clouds add depth to a scene.
Clouds happen different plumose, layered, cumulus, transitional between these clouds, rain, etc.
It is very concrete list of materials which I use. Of course at you can be other tools. Experiment to find sy own style of drawing. F pencils (a pencil softness between HB and B) and 2H from 0,5 mm a mechanical core, a piece of suede (material), Tortillon (a pencil for shading) — small (it is possible to curtail simply paper that there was a pointed tip), Blu-Tack (klyachka), a small ruler, Strathmore 300 Series Bristol Board paper, makiyazhny brushes.
Step 1. We do shading to create tone. I use free position of a hand, only the brush works. Shading at me is executed in three layers by F pencil, 1 layer across, two others on a diagonal.
Step 2. Now the drawn tone is pounded by a rag (suede) which is wrapped up round a finger. Do it several times to achieve smooth tone. Look that pounded everything at the edges, and also buildings, trees and the horizon.
Try not to touch with fingers a paper surface. When mixing there are fingerprints. If they appear, it is very difficult to correct it (if they did not appear in formation of clouds), and many times simply it is necessary to start everything anew! I will add 2 more layers of shading with 2H a pencil and I will mix again. It creates a good smooth surface. By means of a ruler and an eraser make edges equal on each side.
Step 3. Now an eraser create clouds. For easy thin lines in clouds I use a klyachka and simply drag it on all surface.
Step 4. Using a pencil 2H create dark transition near white tops of clouds. Use a pencil for mixing in these areas. Put new tone, shade, shade, erase to reach emergence of clouds on paper. To soften edges of clouds use a klyachka. Remember that if accent of your drawing not of a cloud, they should not compete with other landscape. Usually I use beams of light and hints on clouds in the majority my landscapes. I spend usually 5-8 hours simply over drawing of the sky and clouds. The patience is key in creation of the good sky.
Here example of the evening sky.
Author of Diane Wright, source (site) of www .dianewrightfineart.com
Now can look how to draw the sky and clouds on video from other author.