Upper eyelash edge: pull the outer corner of the eye upwards a little, get the subject to close their eyes and use a brush to place the eyeliner against the upper eyelashes and apply it from the inner corner outwards. Do not start too close to the inner corner of the eye and stop at the outer corner of the eye.
If you want to draw the eyeliner line further, do this while the eyes are open and do not pull the skin. Let the line run a little upwards from a quarter of the way from the end.

You can also proceed as follows: let the eyes open and put a dot on the outside next to the eye in an imaginary line extending from the lower edge of the eye. Reckon with the eyelid fold when doing so. Get the model to close their eyes again and extend the line already drawn to the point marked.

If necessary, thicken the drawn line to the desired shape.
Lower eyelash edge: apply the eyeliner with a brush from the outer corner towards the inner side, but do not finish too close to the inner corner of the eye. If necessary, fade with a dry brush.

Hint: if the eyes are totally encircled, they will look smaller. To avoid this, draw the lower line up to approximately the centre of the eye.