There is no need to memorize all forms, only the irregular ones.
How to know if a form is irregular?
The yellow rectangle gives the tense formation rule.
A verb form in black respects the formation rule: it is regular
A verb form in red does not respect the formation rule: it is irregular
So, when you know and apply the 5 tense formation rules, all you have to do is memorize the forms in red, which means about 7 times less than the total of all forms.
For more information, see the book Pratique de la conjugaison expliquée by B. Hourcade, BOD, Paris