I have designated Fridays as my portrait study day. Tonight I worked on some quick head lay-ins during the warmup, then I moved onto more detailed yet quick drawings of heads then finally finished with a very detailed drawing of a portrait from photo.
I have found Pinterest to have a wealth of information that I can pull from. I have a few boards where I collect photos and information on figures, anatomy, portraits and pure inspiration. Tonight I picked out a portrait photo that had very high contrast to make it easier to pull out the planes of the head. I feel that getting the structure of the head correct is paramount before focusing on too much detail.
These quick head sketches were also done from photos I found on Pinterest.