I will show you the process I do when I draw noses. I found them hard to draw, and I couldn't make them look normal until I found this way. I do find this way time consuming and sometimes I try to draw them freehand. The process does help though.

1.

I start with a simple outline. No ruler needed. I tend to mark out roughly where the eyes will go, the bridge of the nose and nostrils. Tip- start with a light pencil. I recommend HB or H pencil 

2.

Light shading around the eyes and the nostrils. Again, you want a slightly heavier pencil. HB or B, but nothing higher than 2B

3.

I remove some of the lines, which I made in step 1. I then use shading pencils (graphite) to highlight the light and dark areas. I usually use 3B graphite pencil.

4.

This step is similar to step 3. There is heavier shading and using a range of pencil thickness. Usually, for this step, I use 5B or 6B.

I then use an eraser or putty rubber to highlight the really light areas where the light reflects on to it. 

"All Art is but dirtying the paper delicately."  - John Ruskin