Each person's nose has its own characteristic individual features. But, despite the variety of forms of noses, their structure is almost the same, due to the anatomical structure of bones and muscles, as well as cartilaginous formations.
Analysing the shape of the nose, we see that it can be represented in the form of the main surfaces: the anterior (back of the nose), two lateral planes, the base of the nostril surface of the nose. Its proportional structure has different values. Despite this, the human nose has an average proportional value that is approximately common to all noses, which should be guided by when drawing it. The importance of observing proportional relations is obvious, since similarity is the result of the correct construction of a general form with precisely adjusted proportional relations. When drawing the head, in addition to the rest of its details, as a modular size, you can take the size of the nose, which fits four times in height in a medium proportional head.
Before building the shape of the nose, you should start with the basic proportional values, and then determine the slope and position of the nose in space, taking into account the perspective.
When starting tonal modelling, also do not rush into detailed work, first you need to start sculpting the general shape of the nose. When working with tone, you need to come from a light source. Under normal lighting, i.e., from above and in front, the anterior plane of the nose will be the most illuminated, and the darkest will be the nostril plane of the base of the nose with shadows falling from it. The side planes of the nose are under the gliding rays, so the strength of the tone on them will be intermediate.