It is expected you will adapt sessions to fit your resources, time constraints, and particular group of children. However, take care to preserve the intent of a session and its purpose in the overall program.
Read each session ahead of time, several days before leading it. Getting a feel, doing extra research where you feel necessary or curiosity strikes, and following your interests will only make the sessions better.
Preparing with co-leaders is very important. Set up the meeting room, ensure the materials and equipment you need are ready, and be very familiar with the session. Do the Spiritual Preparation exercise together or take a moment before children arrive to share briefly about your expectations for the session.
Keep in mind, and share with co-leaders, all you know about particular children's family situations and personal sensitivities, and how these might intersect with the day's topics. For example, if a child's family is facing homelessness and the story for the day centers on a UU community's actions to combat homelessness, both you and the child may encounter an unintended learning experience. Be ready. Communicating with the other leaders on your team in an evaluative way is absolutely necessary.