Perfect shapes
And now you can start experimenting with the perfect shape. With a nude lip pencil, you don't have to worry about overdoing it, especially on the upper lip, which is usually smaller. For the lower lip, start with contouring from the centre and then follow the line naturally along the lip line. This makes the lips appear visually larger without looking artificial.
Just the outline, or the whole lips?
You can either use the lip pencil to frame just the outer edges of your lips, or you can go from the ground up and use the pencil as a base for lipstick or gloss. If the colour is truly nude, I recommend option B, i.e. to emphasise the entire lip area.