The hot-headed Deidara is something of a sadistic arsonist. He believes "Art is an Explosion!" and with his explosive ninjutsu it's certainly true for him.
I've done the guidelines here with a light grey pencil. A circle for the head comes first. The trick to doing guidelines is to do very simple shapes for your drawing. Once you've got the basic shape and position right, its easy to fill in the details.
After filling in the details with black pencil, I erased the guidelines with white pencil. I used the paint bucket tool and transparent tones to colour the drawing. The shading is done in a darker shade of the same colour.
To clean up, I redid the black pencil outline to neaten the drawing.