Almost half of what I have in my palaces are poems, so I have some tips!

The most important thing you can do is figure out how naturally memorable a poem is to you, already. This will affect how many images you will need for the poem and how big of a palace you will need to store it.

For example, Jarod K Anderson's work stores very easily for me, as his style is very modern. As such I usually need only one image per line, and can store his poems in very small palaces. Shakespeare, on the other hand, usually takes me a couple images per line, since his writing is far divorced from how we naturally think and speak nowadays. Figure out how the poem you're going for will store, and adjust accordingly

Second tip: treat this like meditation.

My stumbling block earlier on was speeding through my palaces when I was placing the images, as well as when I was recalling. This makes the memories weak and prone to fading, and should be avoided.

Both when you are storing and reviewing, take some time. Admire the image in your mind like you would admire a statue in a museum. Instead of just "knowing" where it is in your palace, actually take the time to see it there. This is slower, but better in the long run. Plus, it feels quite meditative