Examiners reports are really good, you can find them on the edexcel website. Generally, what I've gathered, is that examiners enjoy it when you include context (e.g. Great Depression / Prejudice in the 30s) in your essay. With plays, they like to read about your interpretation on the characterisation and also stage directions.
i do a different exam board but we have 'an essay triangle'. In the middle of the triangle its quote, top its language analysis, another point is context and the other knowledge of the play. this will tell u what u definitely need to be writing. in english essays, just try and do as much analysis as possible, you can literally go so in depth with analysis and even make it up tbh