You should learn a couple of poems by the same poet, because there may be a question asking about a poets "work", this means that you can write on more than one poem, which will allow you to write more than just writing on just one poem.
learn more than I'm learning 8 over the course of today to be absolutley comfortable with questions
1 the early purges
2 dulce et decorum est
3 the man he killed
5 blackberry picking
6 those winter sundays
7 midterm break
8 the inter
8 seems a bit much, 6 would cover all themes: What I have:
Lake Isle Of Innisfree
I felt a funeral in my brain
An Irish Airman Forsees his death
Hope is the thing with feathers
And Valentine by Carol Ann Duffy
There we have Naturisim, hope,mental illness, death, solitude, Love,parenthood,children, War, Conflict, Politics, Love and relationships. We studied two of Emily Dickinson's poems in great detail so we have enough to talk about her style EG. Erratic punctuation and sibilance.
No need to cram eight poems into your brain if you have the right ones.
Good luck everyone!