When you begin a drawing, simple guidelines of some sort are helpful. These lines are usually very light and, where possible, are erased before the drawing is finished. If you are drawing an object that is somewhat circular in form, draw a light circle first and place the object within It. This is helpful in establishing the size of the object and its placement on the page If the object has parallel sides, draw parallel guidelines and then place the object within them. If the object is symmetrical (meaning that one half is the mirror image of the other half), start with the center line as a guide. Variations in the outer contours of symmetrical objects can be accurately drawn using guidelines that are perpendicular to the center line. For example, to draw a violin, start with the center line, then draw the parallel lines of the body and neck; next, draw lines perpendicular to the center line for accurate placement of the top, neck, shoulder, and waist of the violin. With these and any other necessary guidelines in place, you can then roughly draw in the violin. If corrections need to be made, this is when it is best to make them. Erase all unnecessary guidelines. Now refine and correct the drawing until you are satisfied.
Symmetrical objects can best be drawn by beginning with a center line. Loose, light lines are then placed at appropriate equal distances from the center line. Lines perpendicular to the center line limit the extent of these lines and accurately locate features on each side of the object. Once the object is established, erase your guidelines and refine the drawing.
This simplified front view of a face starts with an egg shape, which is divided in half vertically and horizontally. To locate the eyes, divide the horizontal center fine of the oval into five equal parts. The eyes fit in sections 2 and 4. To locate the length of the nose and the opening of the mouth, divide the lower half of the face into five parts. The bottom of the nose is usually located on the line between sections 2 and 3 of this division, the opening of the mouth on the line between sections 3 and 4. A nose is as wide as an eye; the width of the mouth is usually equal to the distance between the irises.