The Handbook 2 and the Family Guidebook provide principles for teaching children.
The following provide suggestions for teaching at a child’s level: Teaching, No Greater Call, the Teaching section of LDS.org, and Teaching Children in the Primary section of LDS.org.
Below are some of the key materials provided by the Church:Articles of Faith (8.5” x 11” and card)
Children’s Conference Activities
Children’s Lesson Helps (LessonHelps.lds.org)