For WW1 you really don't need that much detail. Most of it is skill based, you need to be able to read the sources and list answers, and evaluate reliability and usefullness. For the 'your own knowledge' bits, 3 to 4 points not discussed about the topic in the source is usually sufficient. Given how broad the questions are, like "evaluate the effects of the War on the homefronts" or "discuss the trench experiences for soldiers", you really shouldn't have a problem.
Character study, National study and peace and war study are a bit different. Let me use the Russian National study as my example, it should be easy to integrate your own topic on other case studies.
- Remember, you will always be getting a question which asks you to assess, evaluate, analyse, NEVER describe, explain or recount.
- Don't study events, people or situations as plain facts so you can tell a nice descriptive story on the day. Study them as part of an overall argument. For example, say your doing Russia and wanted to summarise the NEP. Studying descriptively is useless to you in an exam, because you need to make your judgements about events while writing your essay. This is not something everyone can do. Rather than summarising and remembering things in this style:
"
the NEP was a Bolshevik economic policy to allow peasants to grow and sell crops to the urban markets"
Study analytically,
"
the NEP was indicative of economic crisis which had beset Russia the past decade, as it represented a fundamental break with Marxist ideology, despite having just fought an exhaustive Civil War to export socialism".
Remember, you will never get a question like "What was the NEP" it will always be "evaluate Bolshevik economic policy" or "assess the extent to which Bolshevik policy was dominated by pragmatism".
- Study by themes. This way, you cover all the content, and you can integrate into your essay something which covers a variety of time periods. Examiners love it when they see essays using evidence from the entire case study appropriately, and not just a shopping list of chronology. Some example themes for Russia:
-Assess the changing nature of the Bolshevik party
-Assess the economic policy of the Bolsheviks
-Evaluate the experiences of the pesantry and proletariat between 1917 and 1939
-To what extent was ideology the main driver of policy in the USSR from 1921 to 1932
etc etc
- Studying by themes also means you might hit the actual question. It's fantastic when you have written a practice essay or essay plan on something you've done already.
