1. Absolutely keep your own set of notes. Be like a magpie: take the best bits from everywhere and gather them together.
2. Type them up. You can't edit them (easily) if they're handwritten, and you want to keep improving and refining them. Also, if they're handwritten you can't send them to teachers, tutors or friends for feedback. You can write them out by hand a million times when you're learning for the SACs and exam!
3. Structure the notes the way you would the content in an exam or SAC question. In other words, clearly know what your core definition is, what your detail is, what your example is, what your strengths and weaknesses are, etc. Use sub-headings.
4. So what content do you cover with all of this? Use the Study Design to help you, as others have said, but also download all the old VCAA exams and sort the questions out topic by topic (that's something I *always* do for my tutor students) - this tells you the types of questions that are frequently asked, the task words used and the usual mark allocation. One mark is 3-5 lines of writing approx, and 1-2 mins writing. Textbooks will frequently have way too much information, or way too little. They also have *extensive* examples, but you don't really get that much for examples in the examination - maybe 1 mark per example, as an illustration? Obviously if the content itself IS a case study, that's different!
5. In terms of resources, I authored StudyON and the CPAP Study Guide, so I obviously endorse them! StudyON gives snapshot summaries of every topic, and has over 500 questions with worked answers. So its focus is revision and practice rather than background learning. So the CPAP Study Guide has much more detail, but we've tried to make it very exam-focused, so it doesn't have pages of 'context' on something that you won't use in the exam. Something we're doing this year with CPAP as well is selling a booklet of the past three years of SACs (that were sold to schools in 2009-2011) with the full marking guide and sample answer booklet. For revision. Anything with sample answers and mark allocations can really help in terms of checking your notes against them.
In my experience marking, significant marks are lost because people don't read the task word and/or respond to the question. Focusing on *questions* is one thing you can do to give yourself a boost. Once you have the content down, obviously!