Exam boards are being helpful...
Exam boards now have a lot of resources to help students and teachers do them. Take AQA GCSE for example... This is what they have on their GCSE chemistry website under teaching resources. First, the command words and the subject specific vocabulary are must reads. The command words are a list of words for the exam questions which explain what the question expects based on the word. The subject specific vocabulary contains terms which you need to know for your investigations