Some of us have a hard time engaging children during worship talks. An extremely helpful resource is "120 Quick and Easy Object Lessons for Children's Story Time" by Jim Simmons. This book provides engaging worship talks geared toward elementary school-age children.
Each worship talk uses objects to teach spiritual truths. Visual aids are captivating, especially for kids. Each one has a Bible verse that should be incorporated into the talk. They also have a handy list of the items needed for each object lesson and often use objects that are easily found in one's home. You may purchase the book at the Adventist Book Center.
One tip for your presentation: Do not read the talk verbatim! Read it over in advance, get the gist of it, and then aim to present with a few notes or none at all.