There is one specific photo that outperforms everything else, and it takes about thirty seconds to shoot.
Full body, facing the camera directly, with your whole body in frame. Not a three-quarter turn and not cropped at the thighs. Put the camera at roughly chest height and keep it level, because phones held at eye level tilt down and visibly shorten your legs.
Stand facing a window during daylight. Overhead ceiling lights carve shadows under the eyes and across the chest, and direct sun blows out highlights that the model will try to reproduce on the fabric. A plain wall, door, or curtain behind you means the model spends its effort on the garment rather than reconstructing your room.
Wear something fitted, like a plain t-shirt with slim trousers or leggings, and keep your arms a few inches away from your torso so your silhouette is unambiguous. That last detail fixes more bad results than anything else, because arms merged into the body force the model to invent your outline.
Take three or four of these once, keep the best, and reuse it. People who save one good reference photo get consistently better results than people who upload whatever is newest in their camera roll.