Use drawingskills to improve your drawing accuracy. Marks that match the model show faintly green. A slight miss turns yellow; a larger miss turns orange. Upload your reference, which will be reduced to its contours.
Make your drawing, then point the camera at your paper, and corrections will show.
Point the camera at your paper and trace the ghost with your pencil. The camera must be still and pointed perpendicularly to the paper, to avoid distortions.
Each reference you upload is reduced to contours automatically, which costs 1 credit. If the image model refuses the picture (often figure or nude studies), a free local line drawing is used instead and no credit is spent.