Hey!
For case studies and written tasks, I found it was usually more effective not to read everything in detail straight away. I would normally start by looking at the questions first so that I knew exactly what I was trying to answer, and then go into the materials with that in mind.
Once I knew what the task was asking, I could do an initial skim of the documents to get a sense of where key information sat and then go back through more carefully, focusing only on what was relevant. When making notes, I would try to keep them really concise and organised by things like issue or question, rather than trying to summarise the entire document.
I definitely wouldn't try to go into the small details at first, as you might spend too much time understanding something that isn't particularly relevant. However, I'd definitely read through everything at least once so that you have all the information and can understand the wider context.
One thing I found particularly helpful was leaving myself enough time to actually produce the answer, rather than spending most of the time reading and planning. It is really easy to spend a lot of the exercise reading and note-taking, but often these tasks are testing things such as prioritisation and judgment as much as whether you have spotted every detail. Sometimes it is easy to put off actually writing the answer, in case you get it wrong, but I found it can help clear things up if I at least put my thoughts down on the page (even if you have to go back and edit it all later).
I hope that helps, and best of luck!!
