Hatching: A method that uses multiple fine lines to give an effect of shading.Cross-hatching further darken areas in shadows. The closer the lines are the darker the area will look.
Stippling: Also called Pointillism is a method that uses multiple dots in shading. The more dense the dots are the darker the area will look. This method is time consuming but very rewarding indeed.
Scribbling: This method is similar to hatching but less uniform. This is a different approach to loosen up and have a unique experience with your medium.
Blending: This is the most popular among artists. Often done with the use of a shading stick, cotton swab, finger etc. This can give a special smooth polished effect. I don't personally smudge but I sometimes use it to selected areas for a smooth blend.
The illustration below shows a variety of methods I used to complete this.
Medium: Pencil on Paper
Artist: Yet Diago
The darkest areas were shaded repeatedly with an ordinary pencil until I achieved the darkest tone in the scale. The farthest mountain were done in hatching and the others in scribbling. I used a cotton swab to blend and smoothen a bit of its surface. A cotton swab was likewise used on the water area to give it a more dramatic effect. The tree was executed in repeated stippling until the darkest of shade in the scale was achieved.
How this was drawn.
Step 1: Outline the drawing.
Step 2: Shade darkest area.
Step 3: Move to midtones; compare to other tones.
Step 4: Work on the foreground.
Step 5: Refine with finishing touches. The water and the sky were refined with a cotton swab.
CONTRAST AND VALUE RANGE
A poor contrast would show a poor value in drawing. Light and shadow create depths; without it, your drawing will look flat. With the correct contrast, your drawing will appear to jump off the paper by depicting the foreground from the background. Providing the image a dynamic lighting gives a dramatic appearance and optical illusion on your drawing.