Before you enjoy this enchanting short film, I´d like to share a wonderful article that has helped me tremendously in teaching the preterit/imperfect. I read it in an applied linguistics class with an amazing professor! Here´s a link to the article, «Preterite/Imperfect Half-Truths: Problems with Spanish Textbook Rules for Usage» by Diana Frantzen.
I also use timelines visually reinforce the concept because that´s what helped me finally understand it. Although, also based on my experience, I think the real key to mastering preterit/imperfect is through authentic communication. Well, that´s true for most everything in language learning actually!
Here´s a link to a PDF worksheet for a writing activity based on the short film: Hoja de actividades: Cortometraje: «Día de los muertos»
¡Y ahora al cortometraje! The vivid imagery is perfect to inspire students to write descriptions using the imperfect, and although only 3 minutes, there are plenty of events to list to practice the preterit. Once students have time to brainstorm their own ideas, we go over them together. I draw a timeline on the board and mark the events as specific points. As students describe the settings/characters, I make squiggly lines in different colors along the timeline. Finally, students combine the descriptions with the narration of events to write a short story based on the short film.
I also recommend this video by the Travel Channel.
Here is a version of this handout on Live Worksheets!