Here is a well over grown head in desperate need of some tidying up.

Perhaps the easiest way to show before and after is by doing half the head. To start note how the ears have been cleaned up so that nothing hangs over the ear. Next notice how the hair on the groomed side of her face frames the face. The stop, the area between the eyes still needs some tidying but the forehead, cheeks and beard have all been cleaned up by carefully removing the longest hairs.

Next is the side view. See how there is no breed silhouette? So lets pulled the longest hairs again and regain that.

See how the cheek hairs have been stripped to frame the face. The eye brows should be slight and not overshadow the face. Important also is not to forget is the underside of the muzzle. That should present a clean shape, again to frame the bottom of the face. Also blend the back of the head into the shoulders.

A few weeks later you can shape the face again. This is how you get layers and gorgeous, full face.