If your prof sucks and you have to read, though, anything in bold or with its own separate heading is usually important to know. Ignore little details (unless they are dates, which you typically need for history) and focus on bigger theories, battles, legislation pieces, etc. For history, you can usually tell what’s important and what’s not in the text by seeing if an event/person/thing had an impact on later events. If they did, they’re important; if not, don’t worry about them.

If that still doesn’t help, I second what other people have said here about buying used books and group study. Professors at office hours are also usually more than willing to help you with outlining important things if you feel overwhelmed with information. Good luck!
References :
-History and Journalism Major
-Poli Sci Minor

A good way to get through some of the subjects is to find some recorded classes like those offered by Itunes U. For example, the Harvard "Justice" series by Michael Sandel is a good introduction to political philosophy and it’s rather interesting and a little bit entertaining. It’s available on youtube.
References :
http://www.youtube.com/watch?v=kBdfcR-8hEY

To work for a republican or Fox you just have to be good at making stuff up.
References :