Select a photograph to use for the portrait stencil. If you wish to create a silhouette stencil, it must be a photograph that shows the face side on, with the features creating a clear line (e.g. the angle of the nose and the shape of the head and hair). If you wish to cut features from the stencil, it matters less what type of picture you have, but it must be good quality to easily determine the subject's features.
Print the photograph onto a rough piece of paper. It does not matter if it is printed in black and white or color. Take the sheet of tracing paper and trace around the outline of the head, carefully incorporating the shape of the hair, ears and nose.
Reverse the sheet of tracing paper and trace back the outline onto the piece of card stock paper. Carefully cut around the inside edge of the stencil so that the shape of the face is removed from the card stock paper.
Draw around individual features such as the eyes and lips if you wish to add more detail to your stencil, again using the tracing paper. Turn the tracing paper over and trace them onto the card stock paper.
Cut around the features using scissors and use the traced image to lay them in the correct place over your full-face portrait stencil when painting over the stencil. These areas will remain blank and show through the stencil, defining the facial features. Spray or paint over your stencil to replicate the portrait stencil image again.