A three-column chart: the singular noun with a picture, the plural in dotted letters to trace, then an empty line to write it again without help. Trees, foxes, dishes, jars, snakes, buses.
Tracing first takes the worry out of spelling, so a child can see how foxes and dishes carry that extra e before they have to produce it themselves. The empty column is where it sticks.
It is a good early sheet for a child who is just meeting plurals, and it doubles as handwriting practice on proper lined paper.