The French paper tests a very predictable set of tenses. Master six and you have four-fifths of what you need.
Present tense: rock-solid on the three regular groups (-er, -ir, -re) and the top irregulars (être, avoir, aller, faire, pouvoir, vouloir, devoir, savoir).
Passé composé versus imparfait: use passé composé for completed actions, imparfait for background states, habits, and descriptions. Practice five paragraph exercises that alternate them.
Futur simple and conditional share the same stem — memorise the stems for irregular verbs (être → ser-, avoir → aur-, aller → ir-, faire → fer-, savoir → saur-…) and both tenses come for the price of one.
Subjunctive is triggered — memorise the top ten triggers ('il faut que', 'bien que', 'pour que', 'avant que', 'sans que', verbs of doubt/wish/emotion) and you will produce it in the right places.