I have started studying for the 1級. I can't imagine I will pass it, but stranger things have happened. I did the same thing when I took the level 2; I took a trial run when I knew about half the necessary Kanji and vocabulary. The next year I passed it. This time is a little different. I have a better grasp on comprehension in general, my vocabulary is probably 5 times what it was then. It's easier to understand written passages, even if it is full of words I don't know.
Still, the level one is a bear, and the passing grade is 70 instead of 60 percent. And I'll be taking 17 credits at the time. We will see how good my time management skills are.
Much is changing with the JLPT after next year. The first and second level will be offered twice a year, instead of only once. There will also be a new test, in between the second and third level, where there is a notoriously large gap. The naming convention is also being changed, from N1 to N5, the "N" standing for 何の意味か全然わかんね。
Registration starts tomorrow, August 1, and ends September 26. In the US, you can register online here. Other countries can find out how to register here. The are study guides all over the place online; the wikipedia page is a good starting point.
A couple of points. When I took the test, there were many American college students who were blown away by how hard it was. Prior to the start of the test, they were asking each other about grammar points such as ～そう、～よう、～らしい. This kind of grammar is 3kyuu, I think. Basic grammar should be well under your control if you hope to pass 2kyuu. I don't remember any questions that easy being on the test.
You will be asked 特別読み方; there were several words like 弟子. Also, there are words like 登山, where your choices are とさん、とざん、とうさん、とうざん. I still remember those, because I got'em wrong.