Meet Big Al Lopez, caricature artist, and National Caricaturist Network member. Exaggerating Big Al is more of a challenge than it first appears. The weight of the exaggeration is around the cheeks and jowls, but the nose and brow also compete for attention. After a couple of discarded loose sketches (being distracted by the nose and brow)...
...I started my third sketch (above) with a few foundation lines and shapes (below), a curved line for the back of the neck, and two circles for the bulk of the face and positioning of the brow.
The curved line at the back of the neck is essential to the exaggeration as it pushes or forces every feature in the main circle into a triangle or pyramid shape, which also allows for exaggeration of the nose.
I didn't draw these lines for my sketch, the ones above are just for demonstration, but I had them in my head when sketching.
The rest is elementary, as the foundation line is doing a lot of the work, one curved line dictating the exaggeration of the features, expression, the lift of his left brow and the extention of the lower lip. You could say I had no part in this exaggeration at all...the lines did it!