Quick questions for experienced tax professionals?

I'm doing taxes for a local Liberty Tax franchise. I've already passed levels 1 and 2, but the level 3 exam was a bit of a bear. There are a couple of topics I did especially poorly on, and I was wondering if any of you could recommend specific study material.

My worst topics were (in order from worst to mediocre):

Resident and Nonresident Aliens

Rental Property (this hurts, I used to rent out a property in the 90's)

Employee Business Expenses (I get reimbursed, so I have very little experience in this area)

Thanks!