Have your students practice writing short sentences in first and third person points of view. For each problem, students write sentences using the clipart for guidance. They write one sentence about the clipart character in first person and another sentence about the character in third person.
This is basic, introductory practice for this skill. This really solidifies first versus third person in my fourth grade classroom. I use this after completing an anchor chart together and they copy the chart into their reading notebooks (and use that chart to complete this activity if necessary).