Some of the differences between a master’s degree and a bachelor’s degree are obvious: a master’s degree is a continuation of ideas you began learning in the bachelor's degree program. But the differences between a master’s degree and a bachelor’s degree in political science go further than simply another two years of school. You won’t just be advancing your own education -- you’ll be advancing a particular body of research, and possibly promoting a particular ideology while you’re at it.
Build on the Knowledge of the B.A.
By the time you enter your master's program, you should have the basics down, which were covered in your bachelor's degree. You should have a solid understanding of the major political systems, ideologies, institutions, and social science research methodologies. You should also have a firm grasp of your specialization -- if your study will focus on liberalism, for instance, make sure that you’ve read Locke already so that you won’t spend a lot of time playing catch-up.
Go Deep, Not Far
A bachelor's degree in political science is meant to provide you with the basic tools to evaluate many different political phenomena. Conversely, an M.A. in political science is meant to make you an expert on particular political phenomena. So while the B.A. is for generalists, the MA is for specialists. When you’re considering a master's in political science, ask yourself if you want to devote a lot of time and brain-power to a very narrow topic -- if not, you may want to hold off on graduate school.
Pick a Side
In an undergraduate degree, it’s ok to experiment. You can be a Marxist in third year and a neo-liberal in fourth year, and no one will blink an eye. But as an M.A. student, you’ll need to frame your research consistently. That will probably mean using a particular ideological framework, but it may also mean using a particular research methodology.
Contribute to Academia
As an undergraduate student, your sole responsibility is to learn. As a graduate student, however, you’re considered a valuable member of the academic community. You’ll probably be expected to contribute to that community in a few different ways: by providing teaching support, by providing research support, and by producing original research of your own.