Your hands will exit the water one at a time, thumbs first. Keep your arm straight as it travels around to enter the water again with your armpit hugging your ear. Slightly rotate your hand as it moves through the air to have your pinky enter the water first.
When pulling, have a slight bend in your elbow. This allows you to catch more water, in turn making your pull more efficient. The best swimmers can use their arm and hand combined as a form of paddle, allowing them to cover more distance while exerting less effort.
It’s important to incorporate a slight shoulder roll with each arm stroke. As you lift your arm, rotate your body opposite from the lifted arm, your shoulder should slightly poke out of the water. In doing this, you’ll generate more force from your pull and your movement will feel more rhythmic.