So I'm curious about how other people study for the JLPT. I don't have the best study habits myself. Generally I study on the train on my way to and from work. I only have a 25 minute train ride, so this means I get a maximum of 50 minutes study time, but it's not the most efficient time by any means. This was enough for me to pass Level 2, but I don't think it's going to be enough for N1 when the time comes.
So what sorts of methods do you use? Where do you study? What do you find to be effective?