linking violence to quotations in Macbeth
To remember all the quotations you need for your exam when the theme is, "violence," use the following mnemonic:
First create a key image for "violence." One way to remember "violence" is the mnemonic of Macbeth standing with a sword just about to be violent and strike someone with it.

Now create a single rememberable image for each of the quotations in Macbeth that relate to "violence." As a first stage we will reference three quotations.
Quotation 1
"Unseam'd him from his nave to th'chops and fix'd his head upon our battlements." This shows Macbeth is capable of great violence.
This quotation can be remembered with the single picture of an "unseamed man".

Quotation 2
"What, you egg! Young fry of treachery." The violent murder of a child highlights the loss of innocence and Macbeth's moral decay.
This quotation can be remembered with the single picture of an "egg."

Quotation 3
"I would while it was smiling in my face, have plucked my nipple from its boneless gums and dashed the brains out, had I so sworn, as you have done to this." The line shows the violence Lady Macbeth is willing to descend to in such an evil way.
This quotation can be remembered with the single picture of a child putting dashes on things.

Now link all of the above images together
Link "violence" to "unseamed man" to "an egg" to "dashes."
See the "violent" Macbeth just after he's "unseamed a man."

Imagine someone going over to the unseamed man and pulling out an egg.

Now see that someone has drawn dashes all over the egg.

You now three quotations from your stock of quotations you learnt that are linked to "violence". If you want more you can extend the story.