Setup to the ball and grip the club as lightly as you can. This is 1. Then, grip it as tightly as possible. This is a 10. At address, your grip should be between those two pressures at a 5.
As you turn the club back, your grip pressure should change from a 5 to a 7 at the top of your swing.
At impact, your grip pressure should increase from a 7 to a 9. This process will give you more consistency and allow you to square the clubface at impact.