if you don’t have a lesson plan, your’re dead, even if it is a rough one. You have to review the material before class. The best time is right after your last class, because you can begin with an evaluation of what went wrong and right with that class, then plan for next week.
suggestions: begin by reading the scripture and CCC citations for the topic given in your Catechist Manual, and pray and mediate for a little while. then go over the lesson, read the suggested activities and supplemental material (which is just suggested, not mandatory) and start planning.
give yourself a structure for each session and it will be easier to get the kids in the structure.
tip: if you show a video or read a story, make sure you have seen it or read it first, know what lesson you want them to draw from it, and how it fits into the topic being presented. don’t let yourself get surprised.
if you are new, try out craft activities and games on your own kids beforehand. I always ask DD about crafts, especially potentially messy ones. She once saved me from having preschoolers step in fingerpaint in bare feet to make prints on butcher paper. She probably saved my job that time. She also warned me not to let 6th grade boys do a craft involving rocks. I did not listen to her, to my everlasting regret.