First draw two lines that look like an oval that forms at the bottom.
Now add the corners of the nose, there is no shading yet.
Now erase the middle line where shading is for most noses since noses don't have lines.
Now add the lines for the nostrils right under the two original lines.
Now shade the inside of the nostrils and outer lines.
Now I've shaded the nose and in the light blue, are the darkest place to shade.
The blue in this pic is for the shading that is medium. The rest is light and u can smooth the pencil using a rubbing stick or your finger.
Ta da!!!! A nose.... Yup... That's it :P