Find soft, even light
Stand facing a large window and switch off mixed indoor lights. Avoid direct midday sun. If one side is dark, use a white wall or sheet to reflect light back toward your face.
Set the camera before posing
Clean the lens, use the rear camera when possible and place it at eye level. Leave enough room around the head and shoulders for several crops. Keep the background quiet.
Capture real variation
Photograph a neutral expression, a warm expression and both slight angles. Change one thing at a time. Select the image that still looks like you and avoid heavy skin smoothing.