It was an interesting exercise. I began by translating the words as literally as possible to see what that sounded like. Most of the time, the literal translation did not work either for meaning or as poetry. Next, I rearranged the word order to resemble English. For example, in Spanish, an adjective usually follows the word that it modifies--the exact opposite of English. Many times, this did the trick. After that, I had to get down in the weeds to tease out how certain words with multiple plausible meanings should be translated. I found the process easier as I went along--the third poem I translated came much easier than the first.
Gustavo Adolfo Bécquer is considered one of the first modern Spanish poets. Originally from Sevilla, he moved to Madrid in 1854 in pursuit of a literary career. Sadly, Bécquer received acclaim only after his death from tuberculosis at the age of 34. [http://www.britannica.com/EBchecked/topic/58011/Gustavo-Adolfo-Becquer]
I translated the following of Becquer's many poems:
Antes que tú me moriré (I Will Die Before You)
Amor Eterno (Eternal Love)
Cuando entre la Sombra Oscura (When the Dark Shadow Falls)