The key to drawing faces efficiently is to look out for facial landmarks. Everyone’s are unique… the things that make people look like themselves.
So far I think Peter (or, Joshua Jackson) is the hardest of the lead Fringe trio to draw. The oddest thing about him is his jaw and chin. Seen straight on here, it isn’t apparent that his chin juts forward a bit, but it can make drawing from a photo reference confusing from certain angles. Seen from the front, his true chin line can be hard to pin down.
Also, one might at first think that he has bags under his eyes, but they’re actually his lower lids and are an important facial landmark to include.
Most artists get his peaked eyebrows right, but they need not be overdone.
He also tends to have small pupils.