The French Society of Dermatology (SFD) provides a focused technical guide on how to conduct a physical exam, including the importance of lighting and identifying "elementary lesions".
A detailed lecture-style PDF covering general and dermatological physical exams (including mucous membranes and nails) is available at Manuel Universitaire .
You can access and download several expert guides focused on dermatological clinical examination and diagnosis. Official and Specialized Guides (PDF)
For a more practical, protocol-oriented approach, the Government of Canada offers a guide on examining skin, hair, and nails, including common types of skin lesions and their associations with systemic diseases.
A 4-page summary specifically titled "Guide de l'examen dermatologique clinique" can be found on Scribd , though a subscription may be required for full download.