I work with soft pastels & pastel pencils using different surfaces depending on the effect I'm trying to achieve. For example, with the above image Red Racing Car I wanted a fairly rough texture to help me describe all of the flaws & chipped bits of paint on the surface of the car. This was achieved by applying a pastel primer with a stiff brush in random directions onto a wooden board.
If I'm after a generally smoother finish I'll use a ready made pastel board which has bit of grit allowing the pastel to adhere to the surface, as in the process of painting Sticks Of Rock below:
I start by sketching the outline of the image, paying particular attention to important shapes & details such as highlights.
Blocking the colours in fairly loosely I constantly assess the look & accuracy of the painting, usually by stepping back a few paces from the easel.
Using the soft pastels I usually put the background in early as well as the darkest & lightest areas so I can judge the colours & tones more accurately against them.
The latter stage of the painting process involves a lot of blending with my fingers & sharpening the finer details with a paper blending stump & pastel pencils. I also use a cross-hatching technique with the pencils to achieve both subtle gradations & texture.