Rachel,
It is a bit late for detailed suggestions about revision. However some suggestions:-
a) Make sure you have a good understanding of your Set Text. It appears - since you are using J&H for your essay question - I take it you are not presenting it as your Set Text. You are not allowed to use the same text as a Set Text as well as an essay text.
b) Obviously I would prefer you thoroughly know your text but if you can focus on WHY you feel this about the text it might gain your marks. Effectively focusing on Evaluation rather than alanlysis - although preferably both.
c) Try not to run round or avoid the question. Even if your argument is weak endevour to always address the question.
d) In RUAE you ought to pick up the U questions: the what is happening questions. With regard to A focus on the language. What do the words mean and what do they suggest? What does the expression mean and - if possible - why has the writer used that expression. This approach will not work all the time, but you might pick up some marks.
r) In the E questions - how has the authors writing affected you as the reader - again focus on thelanguage and the words used and what they mean and suggest. Since the E questions are about how you feel about this quote try to make a response on what you feel.
This is not an approach for top marks, but it might assist in staving off disaster. In RUAE answer first the questions you feel you can answer leaving the others to come back to later. Hopefully that will not be all of them.
Lastly take a deep breath when you open the question paper and don't give in to the urge to make an immediate dash for the Loo.
Good Luck.