Issues with fiscal policy.

The last time I used this tutoring service, I felt much more comfortable discussing materials in class before heading into my previous test...  And the answers I received made a letter-grade difference for me.  VERY HELPFUL-- good confidence builder...

At this point, I need to get a better understanding of fiscal policy, including what it is, how it works, and problems that may arise from it.  I have an exam in about two weeks and am a bit overwhelmed in wading through the volumes of text material encompassing the topic in a macro economics course.  

Can you simplify the above concepts in fiscal policy  by painting a general picture of this?  I think I have the basics down, but am looking for some reassurance here.