Thanks Elvis. To be honest, I think the key to good drawing isn't so much a natural skill but accurate proportions. The first thing I drew was his left cheek. I then compared the length of that to the length of his nose in the original picture and tried to replicate. Similarly, to find correct placement of say, the eye, I knew the inner corner was pretty much perfectly horizontal to the beginning of the ear. So long as you get those key points right, the rest fall into place.
I also did a similar sketch of Bowie's famous Aladdin Sane photo.
