Adrain, IME it was a matter of feeling awkward and gradually finding what worked for me. Here are some diagrams and descriptions that may be helpful. The menu will show the various parts of the face/neck and how to approach them.

Just keep at it and take you time. Focus on skin stretching with the opposite hand and the blade angle. Sometimes twisting the neck, making facial contortions, filling the cheek with air can help facilatate stretching.