The unseen translation can seem the most daunting part of the exam, especially when you have to deal with Latin poets who miss out words and prepositions all the time! Firstly, I would say that vocabulary is key to at least getting a sense of the text, and this will also make you feel better in the exam. Secondly, the best strategy for me was to start with a very literal translation of each sentence, marking out all the verbs and hopefully find a main verb. I would then try to make sense of it in my own head, and attempt to reword some lines so that it was more fluent.