Use this as a start to review irregular preterit groups:
2) BIG 5 / Cortitos (ir,ser,ver,dar,hacer)
3) Sandalias (IR verbs only. E-I, O-U, only in bottom 2)
4) I-Y only in bottom 2 (destruir, construir, huir, oir, leer, creer, caerse)
5) JUUVIS (no accents)
Go through this VERY CAREFULLY:
Remember verbs that normally describe are to be put in the imperfect:
Ser (era), estar, tener, weather expressions (hacer + weather, llover, nevar), querer, DOUBLE VERB STRUCTURES minus empezar & terminar. verbs like gustar, saber.
Try to memorize these verbs as a GENERAL description.
Reach out if you have questions!