Hey foolishangel, try to avoid structuring your essay around characters.
It does make your essay much easier to digest in terms of planning where you can think of all the quotations for each character and slot them into each paragraph, but you will find that it's hard to get depth of responses when you do it this way. Also try to aim for at least 4 paragraphs, 5 to 6 is fantastic but 3 is just not that great at this level. No offence intended, just thought you may as well know now before it's too late

aiming_95, there are multiple ways that you can tackle this.
I would personally define
hardships and what you think that Brooks means by
best and
worst in people, i.e. what values that human beings consider to be of wrong and what actions or qualities that people possess help promote goodness in the world. Talk generally in the introduction about the human condition before you throw in the examples from the novel.
From there you need to find your topic sentences.
What do you think that Brooks is trying to tell us?
You could even follow this guideline: Brooks thinks that the hardships of the Plague bring out both the best and worst in the villagers of Eyam because..
a.
b.
c.
d.
e.
I won't do the thinking for you but here's some questions to get the ball rolling:
How do people react in times of crisis?! What do the characters in Eyam admire in people? What do they despise? Where do they get their values from? What society are they brought up in? What were their conditions at the time? What roles did the individuals play in society? Were females just as important as males? Was status an influential factor in terms of freedom and authority? Were they any cases of persecution? Were there any injustices? Who were the individuals that stood up for the marginalised? Were they commended for their actions, were their acts of bravery recognised, ignored, expected? Why or why not?
Think about the roles that Anna, Michael and Elinor played in the society. Were they expected to act in those certain ways? What happened when they did something out of character? Josiah Bont, John Gordon, the Bradfords and their cook, the Gowdies, etc. etc there are heaps of characters to talk about, not just the trifector.