hey chemistry isn't a very hard subject if you sort your priorities...this has worked for me so far:
1) gain a basic understanding of the syllabus content and know your verbs! if you can't distinguish between 'outline' and 'explain' than you will not get a band 6!
2) further this understanding by doing questions from a textbook (preferably 2 textbooks)
3) make extensive notes based purely on your understanding
4) if you don't understand something....google, youtube, yahoo answers, teacher...you get my point
5) this is the most important step...test your understanding by doing as many past hsc/trial questions as possible. Get these answers marked by your teacher.
6) do not cram chemistry! it is concept based, you will not succeed by memorising!
best of luck