This criterion is highly weighted in terms of marks, and is looking to see that you have good knowledge and understanding of the thematic meaning of the works "under the surface". Knowledge can be shown by plenty of detailed references to the works (plot, character, key moments) and, of course, with quotation. 

Crucially, the ability to compare and contrast is registered in this criterion. And the knowledge shown about both works should be in the context of the ideas of the question in order to gain credit for being appropriate understanding.

This is another heavily weighted criterion, and the explanation of what analysis and evaluation means and how to develop your skills in this area is explored more deeply in Paper 2 - Analysis and Evaluation. 

Overwhelmingly, this is where an examiner would expect to see and would reward explicit discussion of the literary features specific to the genre being studied. All too often, students only discuss plot, character and theme, therefore failing to give (and receive) full credit for appreciation of the tools of the trade and the craft of the writer. A playwright, after all, has many different considerations and employs a different skill-set to a poet and a novellist. Thematic meaning and message is key to a writer, why they write, and to the value of the literary art, but to score well in analysis and evaluation, deconstructing the way that theme is crafted and conveyed is essential. 

Also important here is what used to be called "response to question". A well-structured response - as outlined in Paper 2 - Structuring an Essay - is always explicit in how the point that is being made connects to the question and the overall, analytical argument. So clearly and effectively articulated reasoning as to how any paragraph connects to the overall question is rewarded here.

This criterion considers your own structure and organisation of response. There are a few things an examiner considers beyond the more holistic "does it feel well-organised?" question:

Are the basics there? Is there an introduction (one that addresses the question in the first sentence of the response, and that sets out a thesis statement as a "map" of the essay)? Is there a conclusion? 

What is the overall word length? I would suggest that essays should be between 800 and 1000 words in length (in 1 hour and 45 minutes). Much less that that should be penalised in criterion A, but probably in C too. I would say the same for essays that were considerably longer than that, as they probably lack sharp focus.

Are there clear analytical points as the topic sentences of each paragraph? I would suggest following the "Author-Choice-Effect" structure - Miller uses a biased narrator to highlight the clash of cultures between Italian and American justic systems - that create a sharp connection between the craft of the author, the tools they use, and the thematic question being answered. But essays that have 100 words of plot re-telling at the start of each paragraph before they get to an analytical point just aren't well-organised enough.

Body paragraphs - are they equitable in length? Essays with one or two very long paragraphs and other shorter ones always get criticised. Is each work given equal weighting in the essay? If not, marks will be lower. Is the essay comparative in structure? I propose one body paragraph about one, one about the other, and then one about both. However, ensuring each body paragraph is about both works also solves the problem. But it must be comparative in structure - not just with some comparative conjunctions, like "similarly" - and each work must be considered equally.

Are quotations used and embedded within the essay effectively? This is another skills of literary organisation. 

Traditionally this is the criterion for which inexperienced teachers and examiners undergrade students. At Standard Level at least, as long as the essay could be understood by the examiner with some attempt at a formal register, the student would gain 3 marks. At Higher Level, there usually needed a little more accuracy in terms of punctuation (the basics of capital letters and full stops, rather than the curse of comma-splicing), and the titles of the works needed to be cited at least semi-accurately (they should be in italics, of course, or underlined when handwritten, for novels and plays. Not speech marks. But poems should be in speech marks, with the collection in italics). 

Most serious students with a strong level of language should be able to get 4 marks in this criterion, especially if they use some technica terminology when discussing the literary features. However, it has always been very difficult to get 5, for it requires high-level vocabulary used appropriately (and sparingly as necessary), and involves such careful precision and concision when writing. Less can often be more with this criterion; there is rarely much benefit from swallowing the thesaurus!