The posture we assume during Gongyo is an expression of our faith in the Gohonzon. It is important that we assume a dignified posture, which is both fresh and solemn. You should sit with your back straight, while your eyes, filled with gratitude, look straight at Nam-myoho-renge-kyo inscribed down the center of the Gohonzon. During the silent prayers, keep your palms and bow your head naturally.
Gongyo and chanting constitute the basis of our faith, the prime point for accomplishing our objective – that is, our human revolution. Therefore, it is only natural to observe Gongyo in the most respectful manner and with an earnest attitude. Bearing this in mind, please strive to improve your Gongyo accordingly
When two or more persons observe Gongyo together, the participants should recite the sutra and chant daimoku in complete harmony with the one who leads. This is vital from the viewpoint of the principle of itai doshin (many in body, one in mind).
Suppose that all members of the family begin the day by doing morning Gongyo together. Even if your child belatedly joins somewhere in the middle of Gongyo, he does not need to start from the first prayer. The fervent prayer of the parent will complement the part which the child missed, so great is the power of the Gohonzon. However if your child, taking advantage of this, makes it a habit to join in late, you should of course correct him.
Source – Guidelines of faith by Satoru Izumi