Answer:
I know it sounds stupid but I use the style of Eminem's "Lose Yourself" for the present and I just remember that ser and ir conjugate the same in the preterite
Present - Soy, eres, es (eres, es) somos sois son (somos sois son) and thats to be (and thats to be permanently)
Preterite - Fui, fuiste, fue, fuimos, fuisteis, fueron