Lining up with the guides

Using the reference plate for the side of the face I started to line up the vertices in side view.

I started by moving the middle vertices into place and then continued moving the next vertices along and so on.

It got very confusing when moving the vertices especially the vertices around the eye as they had to overlap.

When moving the vertices by the nose I thought that I would need some more vertices to create the bridge of nose.

 

I added another edge for the bridge of the nose and then used cut tool to add in another loop around the eye to make sure that there were no triangles created.

 

I joined this new loop into the existing loop under the eye and adjusted the topology to make sure that only quads were created.

This is the final mesh at this stage, next I will add  a symmetry and a turbo smooth modifier.

This step was the most difficult part so far of creating the head model. It started off being quite difficult but then as more of the vertices were in the right place it was easier to place the remaining vertices.

I found that the two reference images didn't line up exactly but this wasn't that much of a problem as having already placed the vertices in the correct place in front view meant that I only had to move them along one axis.