If there's one book I'd say was well worth students buying it's a book on study skills. It's excellent value as it will apply to every course, not just one. I don't know that I'd recommend any particular book as what works for one person doesn't always work so well for another, but this one is new in and gets lots of stars on Amazon, so it might be worth a look.
McMillan, Kathleen. The smarter student: skills and strategies for success at university. (Floor 1 - Study skills section - 029.6)