Too much tension in your hands prevents the club from swinging down and through the impact area properly. The feeling you want is that the clubhead is "releasing" past you. You can't do that with a stranglehold on the club.
2. FLEX YOUR TOES UPWARD
If your hands and body shift out toward the ball—setting up a shank—your weight moves onto your toes. So one way to prevent shanks is to keep your toes flexed upward inside your shoes. That will keep your weight back.
3. HOLD YOUR CHEST HIGH
Some shanks are caused by diving into the ball with your head and upper body like you're chopping wood. Avoid this by keeping your chest up through impact. Don't change the spine angle you established at address.
4. KEEP YOUR HANDS CLOSE
As the club moves through, focus on the grip end staying near your body. A good drill is to put a tee in the ground just outside the toe of your club at address. Miss the tee at impact, and you'll hit the ball in the center of the face.