This song activity is great for aDía de muertos unit! Also, for my more advanced students in a Spanish Conversation and Composition course, I used this activity together with the story “El otro círculo” by Luis R. Santos (as featured in our textbook, Revista). We compared our analyses of both the story and the song to discuss different cultural perspectives about death presented through literature, art, music, etc.
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!
¡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.