my advice is to purchase two well written books of islamyat with respect to css then select the imporatant topics from past papers then read the same topic from both books, it will increase your writting capability and clear your concept in a better way
second the topics which make you confused, if those topics are covered on the which you have then make a hand made notes. it will gives practise and while you are practising you will develope more and more ideas beacuse. these topics are really and daily basis matter for us, so try to concentrate more on notes. and internet also have some good websites about islam so you would also get a good material from there, and it also saves time, to reach to the prescribed topic
and as well as you talked about short span of time.
so i would like to tell you that devide your notes into three form
long notes
short nots
and
revision notes

now i would suggest you to make short notes and revision notes, beacuse exams are very near. i think you will get my point (i hope so)


best of luck

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