Lots of people seem to hate the JET programme's free language books. Mostly cause there is a list of words in each chapter, and the book tells you to find the definitions yourself. I came to appreciate it though; typing all those words into the wwwjdic site got me used to typing in Japanese, and helped me memorize which words have long vowels.
Last month I tried something new; I checked off the words I knew and studied the words I had learned up to that point in the book each day. I really wish I would have started doing that before this month's book (it being the last). Oh well, there is always the translator's course I will probably take next year.
Anyways, it was a bit of a time cruncher, so there were a couple chapters I didn't do this for. I also started scribbling out the furigana above the words to make sure I completely knew words before checking them off.
BTW, no more essays to subject you to, cause the last book doesn't have that sort of test. However, I may well try doing a sort of language-blog exchange with my gf; having her correct me through skype was most helpful.