How can I learn to recite a poem?
Reciting poetry can be a tricky task, especially when the chosen poem is long. Luckily, you mentioned your assignment is to recite I Have a White Rose to Tend, which is quite short. Translations from the original Spanish are readily available, so perhaps the difficulty of your assignment lies in learning to recite the poem in its original tongue. I hope the following tips are helpful to you.
When learning to recite poetry by heart, it can be helpful to listen to others' readings of the poem. Perhaps you can find a video available online of someone reciting this poem in your preferred language. Close your eyes while listening and take note of the rhythm and pronunciation.
Another helpful tip for memorization of any kind is to practice by hand-writing whatever you are committing to memory. Try copying this poem by hand and see if it helps your memory!
Consider making use of associative memory. Think about each phrase or verse of your chosen poem, and create either a mental image or a physical gesture to go along with this phrase. If you know sign language, or are willing to learn some simple signs, having some motion to go along with your speaking can be helpful in your memory process.
Finally, I recommend you seek the aid of a friend or family member. You can print out the poem-- or offer them your hand written copy-- and you can practice your recitation with them. If you are stuck and can't remember what line comes next, have your practice partner prompt you with the next word in the poem. This should help you recall the phrasing.
As a general study tip, try reading over your chosen poem (or study materials) right before you go to sleep at night, so that it is fresh in your mind. Short-term memory is converted to long-term memory while we sleep, so if this poem is the last thing on your mind before you go to sleep, it is more likely to become a long-term memory!