Whiskers - There are very sensitive nerve receptors at the base of your cat’s whiskers. They will move them forward when they’re interested in something and feeling calm and friendly; they’ll hold the whiskers back against the side of their face when they are unsure or upset.
Ears - Cats will rotate their ears in different directions to better listen to multiple goings on. When your cat is relaxed it will hold it’s ears erect; when frightened or angry, out to the side; and when very agitated, fully flattened to the back of the head.
Eyes - Your cat’s relaxed eyes are open with normal pupil size, when your cat becomes fearful or angry the eyes will fully open with large dilated pupils.
Tail - A happy cat has an erect tail; when the tail is horizontal or low to the floor the cat is cautious or scared.
Vocalizations - Cats have a variety of meow sounds and they will hiss and growl defensively.