Well, it really depends on how much time you've got to prepare and how much work you want to put into it. I haven't used Wheelock's textbook so I'm not sure exactly how much material you're supposed to have mastered but if your teacher said you only need to revise Present, Imperfect and Future Tense, it shouldn't be too difficult for you to get to grips with that in a few days.
The way I went about learning how to conjugate verbs was: I made a list with all possible verb endings. Once these were sorted in a coherent way, according to Tense, Mood, Voice, Number and Person, I conjugated all verbs I came across until I was confident in recognising different verb forms at a glance. (It's important to remember in which conjugation a verb is.) I remember it taking me about half an hour to fully conjugate a verb in all its possible forms, but it should take you much less than that.
Next, vocabulary. I consider flash cards the best way to learn vocab. Write the nom. sing. and gen. sing. form of a noun + gender on one side and the translation on the other; for verbs it's crucial to know the four principal parts and whether a particular verb takes a particular case (for example verbs of condemning take the gen. to express the penalty).
Make sure you've read all texts you are supposed to and can translate them. And if you want to go the extra mile, translate the texts in writing and then try to write them back into Latin a couple of days later.
Hope this helps and good luck!