So, I occasionally will get the itch to draw, but I keep running into this - I cannot draw a realistic looking nose.  What is the great secret?! 

Noses can be tricky...different shapes, sizes, angles...I'm far from perfecting them myself and being a cartoonist I tend to go for stylised rather than realistic. All I can suggest is finding lots of pictures of faces and practice drawing them.

Visualization in 3D space. Break it down into a shape out of squares or rectangles and simplify it. Then get used to how that roughly looks from different angles so you can re-draw on demand. YouTube tutorials like those of Proko might help you.

Why did I never think to Youtube this?  Gah.  Thank you both for your suggestions.