Ask the photographer to take the photo from a low shooting position with an upward angle that can create the illusion of height.
Extend one leg forward and point your toes. This elongates your body and can make you look taller.
Slightly angle your body to the side instead of facing the camera head-on. This can make you appear taller and more slender.
Capturing photos while you're in motion, like walking or jumping, can give the impression of height.
When sitting, choose a higher seat or cushion to sit on, making you appear taller in photos.
Stand up straight with good posture, chin up and shoulders back. Slouching can make you look shorter in photos.
Leaning slightly toward the camera can make you seem taller and more prominent in the frame.
If you have props or backgrounds with vertical lines, position yourself near them. Vertical lines can create the illusion of height.