The first job of the coach is to teach a beginner the correct grip. The correct grip is a building block to achieve a more consistent and successful squash swing. If the grip is incorrect you are going to learn bad technique and the swing will not be as adaptable as it should be. The biggest obstacle for any beginner is to not hold the racquet like a club. Although this poor grip will have short term rewards you must persevere with the correct grip. The initial learning curve will be steeper but the long term rewards will be far greater. If you make sure the grip is correct at the onset, it can then be eliminated when fault diagnosis takes place later in the development path. It is a common misconception that the grip changes from forehand to backhand shots. The only difference is the pronation or supernation of the forearm.
Figure 1 shows the spacing between the fingers and the amount of the grip the hand should cover. This spacing gives greater control over the racquet and more feel when striking the ball.

Figure 1
In figure 2 you can see the V shape created. It is almost as if you are shaking hands with the racquet. The hand is slightly off centre which allows the face of the racquet to be more open on impact.

Figure 2
Figure 3 shows an extended index finger on the grip. This has the biggest impact on the control of the racquet. Keeping this trigger finger extended maintains your control of the racquet.

Figure 3
In figure 4 you can see that I am not strangling the grip of the racquet. Although holding it firmly there is no tension in my fingers. You should hold the racquet in the fingers not in the palm of your hand.

Figure 4
This rounded grip will enable you to develop the rest of your game. Now that the most rudimentary aspect of the game is in place, you can confidently work on the rest of your swing.