I think that two particular approaches could help out here. The first would be to have an ongoing word wall in the classroom, if possible. This accomplishes two fundamental goals. The first is that the word wall represents constant exposure to the words, allowing you easy transition between the literature being read and the vocabulary present. Another approach here would be to start integrating the vocabulary in different settings. I would try Mad- Libs as a starting point, with the stipulation that only words on the word wall or words encountered in the literature can be used. Having prizes for what the class votes as "funniest" or "best" Mad- Libs can help make this a contest that kids will enjoy. Another approach would be to use online resources to help students study and prepare. There are online sites where students can create virtual flash cards of the words and their meanings and synonyms as well as play games with the virtual index cards they make. This might help make vocabulary acquisition both more meaningful and something that is more engaging to students.