As a General Studies "Lecturer" I would advise using a revision guide to test your ability to write for periods of time about the given issues and questions raised. Reading over your notes from the year (depending on the quality of your teaching) is advisable also. Furthermore it is worth noting that General Studies covers such a wide area of knowledge that there will certainly be key terminologies you could memorise; for example you may be asked about medical ethics - are you familiar with "informed consent"? I'm sure you can guess what it means, but it is wise to find real-world examples of key terminologies to support whatever argument you may have to make.
Broadly speaking in essay answers you will be marked on correctly identifying general issues around a given subject (hence the title of the course) and being able to argue well. Your essays should follow a standard format with an appropriate introduction & conclusion and must be written with PEEL in mind; P - Point (make a point), E - Example (give evidence to support your point), E - Explain (now explain what this means), L - Link (build up to the next point, following logically on from the one you've just made; use a linking word such as "Furthermore" or even an opposing term e.g. "By contrast")
The nature of the subject makes specific revision very complex - you could be asked almost anything in theory; but your responses will be based around an ability to argue. Don't revise anything you know you can talk about (for instance, if you're really into Politics you probably already know the key terms and real figures you'd include in your essays). Revise things you don't know so well (sounds obvious) - perhaps business is not your strong suit; revise from your notes, swot up on real-life businesses/corporations and types of deals they make/can make etc; memorise some general points around the pros and cons of having private enterprise over public service, the benefits and disadvantages of having CEOs etc.
Your revision also depends on who your exam board is: I "lecture" in AQA General Studies (B), which involves only a small amount of Maths, but Edexcel papers can involve more mathematics (though most marks will still be essay-based). Practice how to make percentage changes in calculation and so on. Simple formulae that will be easy to use when analysing graphs. Don't forget to show your working out (in AQA)!
I know this post is old, but I hope current students may see it. There is a misconception that General Studies is "easy" and all you need to do to pass is "read a newspaper". Broadly this is of course advisable, but the subject is potentially one of the most difficult of all - your base of knowledge has to be HUGE and demonstrative of both contemporary & historical awareness. Passing might be straightforward (though many students actually fail), but doing well is likely to be extremely difficult if you are not naturally interested in general knowledge.
I got 100% when I took the subject as a student, and now I "lecture" in it. If your university accepts it as a valid qualification, you should revise, because the marks are straightforward, but if not then yes, prioritise your other subjects. But try to revise something!