In backstroke it is important to make sure that each stroke is evenly parallel to your body to make sure you are creating as much power on your pull

Make sure during your stroke that your head is staying still even as you are rotating your shoulders.

For backstroke kick it is important to point your toes, and use your whole leg as one unit. If your knee is coming out of the water on each kick, it is bending too much!

During your backstroke, stroke it is important to flick your pinky as soon as your hand leaves the water. This will rotate your shoulders and enable you to grab more water as you re-enter the water with your hand