I have my students keep a vocabulary workbook, in which they are required to add an average of one word per school day, of their choice, from reading materials or the media. It must be defined in English, with an example, and be dated, and I have them consecutively number the words, so that I don't have to count them. :)
I also reward them for using words orally that they have previously recorded in their vocabulary books.
This means that reading is the source for vocabulary growth, and lists with quizzes are never used. That method doesn't work.