1) You will take six picures - 1x front, 2x 45°, 2x profile, 1x back - profile and anfas (front) photos have to be perfectly straight.
2) Do not make any expressions. Just relax.
3) Focus on the body and the head - so the resolution of the pictures is as high as possible. Do not take a picture of the head only, because it may distort the proportions.