This PowerPoint reviews virtually everything your students need to know about the preterite tense.
It begins by reminding them what the preterite is used for (with example sentences), and reviews the regular preterite endings. They then complete a short conjugation practice (answers can be shown on PowerPoint afterwards).
Next it delves into verbs that have an i --> y spelling change in the third person (such as leer, creer, destruir, etc.). After seeing the rules, they do a conjugation practice specifically about these verbs.
The next several slides review irregular verbs. Specifically: tener, andar, estar, poder, poner, saber, venir, decir, and traer. You can pop the forms up one at a time, or all at once. Then they do another conjugation practice just about irregular verbs.
Next is section about verbs with e --> i and o --> u changes in the third person. (ex.: servir, pedir, repetir, dormir) After showing them the rules, there is yet another conjugation practice for them to try, specifically geared toward these verbs.