The first was based on a specific photograph, and it shows. There is too much simple 'drawing' and no 'caricature'. Nor is the likeness terribly strong.
The second - based on another photograph - was a bit of an improvement, but superficial parts such as the line of the hair are still the unnecessary focus (the decision to use straight lines was here a bad one, not fitting with the overall shape of the face), with too little effort to capture more than simply Hitchcock's appearance. Again, the eyes are too prominent - another failed attempt at heavy eyelids.
It was only with the third Hitch - which is still, I freely admit, far from perfect - that I felt I caught the 'essence' of Hitch rather than simply his appearance. Notably, this is the only one that was not based on a photograph. Not relying on a single image forced me to focus on the subject himself rather than a single representation of him. I finally managed to get the right character in the face, and, as with Hirschfeld, it turned out that the fewer lines, the better. The slightly pompous lower lip, the disdainful but lazy glance, and the haughty nostril all work best when shown in as simple a way as possible.