The most important thing to remember at GCSE is clarity and confidence. When you first encounter your unseen text, it can be overwhelming, but it's important to remember that once you're in the exam, you can focus on what you know and recognise in the text, not what you don't understand. My first tip is, put your pen down! This might seem counterintuitive, but if you read through the passage several times without forcing yourself to plan or write, you'll crystallise a much better understanding of what's actually going on. After this point, and before planning, having half a mind to the mark scheme for your answer is best. There is no point in preparing for a long essay answer if the question only called for an analysis of specific features or characters! For a generalised commentary, it's worth taking a few different colours of highlighter into the exam (remember, your exam paper is your own, you can scribble and colour and all you need!). Here, you can pick out language features that you've revised and prepared when you've studied, highlight them. Then you can pick out structural features. Any passage or poem will have an arc to what is going on, so you can then jot down in the margins what is happening. Finally, preparing an introductory sentence to summarise what is going on, and a concluding one to round off how these language features and structures contribute to the meaning of the passage will make the main body of your essay have a clear direction. From there, planning two or three clear paragraphs and assigning features you'll comment on to each will make your essay much easier to write, and the initial overwhelm of an unseen text seem a distant memory.