Read the extra t carefully, and mark/annotate/highlight sections that seem important
then, select/underline one or two of these important bits that seem to be the key points - these should be the focus of your presentation, or the angle of your approach
think about the extract as a whole, and the important bits in particular, relate to the work as a whole to what the work has to say
decide what (limited) reference to the rest of the work you need to make in order to deveopl a clear explanation about the extract.
make a brief plan, or map, showing the running order of the various comments you are going make about the extract
devise a brief introduction, along the lines of 'this extract is about... it comes from the point in the book when... it contentrates on the theme of...'
after the introduction, summarise your plan, or map, very quickly:
first I'm going to talk about...
then I'm going to explain...
finally...
if you can wrwite a brief conclusion, and aim to get there.
Above all, emphasis that 'effective use of the extract'(top mark band) means explaining each step in your argument clearly and backing each step with reference to the extract itself (and, to a limited extent, to the context of the work as a whole)
the better marks were awarded to candidates who gave detailed readings of the extract i.e. referred often to specific quotes, and explained what they meant. In other words, a detailed commentary or read-through of the extract. These detailed comments might well be then linked to general comments about themes in the work as a whole, but these general comments were short, clear, and well-focused.
Middling marks were given to those who might talk mainly about the extract, but with little reference to quotes or to details in the extract - the generalised remarks were sensible enough, but were little supported and did not illuminate understanding of the extract in detail.
the lower marks went to those who mainly talked about the text as a whole - such as a general summary of the story, general comments on what the author wanted to say, even background information/period, etc, even if these were quite well explained and organised. Although many good presentations might include a brief introduction about the work along these lines.)
In short: students are advised to base their presentations on a detailed commentary on the wording of the text, and train themselves to deliver this.