Hey, totally ****ting it for the exam too but I think (end of) Detente and Arms Race might come up, so try and learn those the best.
I've covered detente by making a timeline of detente and key info like what helsinki accords contained and what SALT 1 contained etc etc.
I've then categorised what brought about the end of detente (that being ussr invasion of afghan which is probably the most significant) then the failures of SALT like both superpowers contradicting detente such as usa developing MIRVs+ carter launching trident and USSR violating basket 3 of helsinki, ussr taking third world countries to its advantage and their style of adventurism- which links with the contradicting nature of detente, brezhnev's health was also declining which meant negotiation was weak and it gave an advantage for neo conservatives such as brezyinski to influence carter more and obviously regean and thatcher coming to power in 1979-80. But afghan war was most significant because it was basically a proxy war and you can't have detente whilst both superpowers are in a proxy war, also carter like removed SALT 2 from the senate, stopped trade of grain and tech and increased military spending on arms. So yeah detente pretty much died in 1980.
Then obviously the factors of how detente was a success well it's pretty much just the summits and negotiations and the arm limits etc etc, that bit's easy to do.
Also look at the needs of the USA and USSR. US wanted out of vietnam + their economy was stagnating and USSR economy was completely **** and they couldn't afford to concentrate their money on arms and military.
Sorry for probably the million spelling mistakes I just made but do the same thing for arms race, get the key information and significant events and make a timeline. But remember in the section A exam to ALWAYS link everything you make to the question.
Section B I feel pretty ****ed on because edexcel is an asswipe exam board but if I do any further revision etc I'll post it on here.
Hope it helps.
pss// edexcel revision notes/ the edexcel revision textbook will do you amazing help. Or the CNN documentary which is on youtube.