I like to base my History notes on the 5w's - what, where, who, when and why (+effects) - which really does help with identifying the key features of certain events etc. Definitely don't cram - perhaps set yourself a target of revising ten events, for example, each day alongside your other subjects.
In terms of past papers, do as many as you possibly can all by hand. Start off slow, with your notes open by your side before doing them under timed conditions a couple of days before your final History exams. Also, annotate as much as possible on the question sheets so as to ensure your answers contain as much information as possible; I find this helps to stop my mind racing at about 150 mph out of sheer panic and, thus, help me focus on writing good responses. For instance:
Explain the key features of the Long March or the Hundred Flowers Campaign
Hundred Flowers (1956-57)
- A campaign launched in retaliation to the growing critique he was receiving post-Five Year Plan
- Attempted to weed out any and all intellectuals (e.g. teachers, artist) and create law-abiding citizens
- Initially was open to critique, though this changed after he saw the severity of it; did not want to be overthrown much like his predecessors (e.g. Manchus, Yuan Shikai, Chiang Kaishek)
- Created democracy walls that could be easily monitored so as to identify any and all intellectuals
- Once these people were identified, they were subject to struggle sessions in which people accused them of (usually false) claims that involved them being disloyal to the CCP - these would continue until they practically begged for forgiveness
- Should then not "budge", intellectuals were then sent to labour camps (laogai) for re-education
- Over 500 000 intellectuals died over the course of the campaign, thus setting back China's artistic development by many years; few people dared to speak out against the CCP over fears the same thing would occur to them
- When asked why he allowed the campaign to occur, Mao cited the Hungarian Uprising (1956) in the Soviet Union as his excuse for starting it; he wanted to quell all revolutionary ideals so as to maintain power.
... And then you turn all of that into a paragraph or two.
Hope this helps
Also making timelines but including descriptions of events underneath. I've stuck mine on my wall next to my bed and it's really helped me remember everything!