By Margaret Orleans
Dave and Jane Willis (authors of the CoBuild series) suggest for a pre-reading activity having students skim a new passage and identify a limited number of words (say five) that they think are the most important for them to know before reading the passage more carefully. This can lead to fruitful discussion among small groups of students, sharing explanations of words that some but not all of them know and searching for as many contextual clues as possible.
I agree that this is very fruitful because it helps students create the links that will enable them to access the words from memory through various routes (rather than just Chinese-English equivalents), but it is so time consuming that it cannot be effective by itself. It's better as a model of how they should be dealing with words when they learn them--not just simple lists that gather dust. But in fact, students need to be learning hundreds of new words every month and the best (but not always practicable) method for retaining them is through constant exposure in new contexts--which means wide reading and listening.