Cats do not take direction, so build the shot around their routine. Pick a spot with soft window light where your cat likes to sit, and get down to eye level.
Use a burst or tap to focus on the face, then pick the sharpest frame. Make sure whiskers, eyes and any markings are visible. Avoid flash, which flattens fur and makes eyes glow.
A quiet moment after a meal or a nap is usually best. If your cat is moving, a slightly slower approach with a treat or a toy just outside the frame helps.
Upload your favorite photo, choose a theme, and see what comes back. The same advice applies to rabbits, birds and other small pets.