When starting to do an illustration I always do several small sketches to establish the composition. Often art directors will request sketches like this to see if that artist has understood his instructions. This is a very important step in creating interesting illustrations.
I received an interesting assignment while living in Paris, it was an illustration of Phebus, a new French space satellite. At the first meeting with the client I was asked to submit pencil sketches, these are a couple of them.
They approved this version which gave me a clear direction to go for the final painting.
Here is a more accurate compositional sketch, it was done using black and gray markers on layout paper.
The final painting which was done in acrylic paint.
Preliminary sketches for the cover of my Drawing In Ink book.
The final cover, this is the Japanese edition. The final drawing was done in in using a pen and a brush.