I like Marks idea of keeping a notebook of your practice.
It may prove to be of encouragement at times -
also, you have a distinct advantage...you speak the language (unlike what I have gone through in Hungary) so you can listen to the explanations and variations that are being shown, pick up on terms etc. to help on memorization...and ask questions.
In my circumstance, I have found it also quite useful to go in with purpose.
That is be proactive to find out what the testing requirements are - to familiarize yourself with the japanese terms so that when they cry out shomenuchi, etc your not translating in your head "ok. this is strike to the head' or even worse, "wow what is this new term" - but when they say shomenuchi you will picture a bokken going to the top of your head (real way to learn language as constant translating in head will slow you down and drive you nuts...
also, coming to this forum has been both fun and quite informative...and the key to it all is...
...just have fun!