Being a catechist can be a difficult task, especially when someone is volunteering and does not get reimbursed for their time. It can be especially difficult when the students do not appear to be learning anything or taking it to heart.
St. Charles Borromeo is a great saint to turn to in such a circumstance as he is the patron saint of all catechists.
He wrote some simple advice in a sermon that is featured in the Office of Readings.
If teaching and preaching is your job, then study diligently and apply yourself to whatever is necessary for doing the job well. Be sure that you first preach by the way you live. If you do not, people will notice that you say one thing, but live otherwise, and your words will bring only cynical laughter and a derisive shake of the head.
The advice may be simple, but it is also very challenging.
St. Charles is not alone in echoing the advice to "practice what you preach." Many before and after him have pointed to this phrase as a foundation for teaching the faith.
If you don't practice what you preach, your students will not think it is possible to fulfill the many demands of the Gospel. Instead, they will laugh and shake their head, thinking the faith is nonsense.
Yet, if you do live in a way that is consistent with the Gospels, your students will recognize it and will see a living example to follow.
If you want to do anything for your students, practice your faith openly and with great conviction.