This flat was drawn on adobe illustrator. Notice each side is perfectly symmetrical, all topstitching is indicated clearly, you see the shape of the neckline & armhole clearly, and the drawstring tunnel at waist. The draw cord is left untied so the pattern maker can see the spacing between the eyelet's the cord comes out of.
If drawing by hand, don't be lazy... use a ruler and keep all your lines straight. Usually, a thicker line pen is used for the outer edges and seams and a finer line is used on topstitching and buttons.