The preterite tense is always a struggle. My students have done exceptionally well and actually like this HURRICANE method. Just like HURRICANES, I have divided the preterite into categories - building up to the most difficult. We work through memorizing the category endings and then, just like multiplication charts, we practice placing the verbs in the respective categories! SUCCESS!
(NOTE: take the last page of this and copy it - cut it out and paste it onto page two. Then print off as a two sided sheet. I laminate mine for the students, as we get a TON of use out of this)