"It seems like the children I teach have a shorter attention span than ever before. How can catechists capture and maintain children's attention?"
It can be a challenge to get and keep the attention of young people today.
Be sure that your activities and supplies are organized and ready. You don't want to risk losing the group if you have to pause to prepare an activity. Break the session up into several smaller parts, and switch activities often. Try to use multiple senses (e.g., auditory, visual, tactile) as much as possible, either in a single activity or across several shorter activities.
Give positive reinforcement in the form of encouraging words when you see your learners paying attention and participating. Let them know you appreciate what they are doing.
Most importantly, communicate through your own enthusiasm that you are really excited about the message you hope to pass along to your learners. Make sure you move around the room and interact with learners during your lessons. Let them hear from the excitement in your eyes and voice that you mean what you say. There is no replacement for the witness of the catechist and his or her commitment to the message.