So, I'm going to Japan in about a week and a half (12 days and counting!), and I was wondering if there was anything I should know before I go there. I've taken 4 language classes at my University, so my grammar is probably at maybe a grade 2 (Japanese native) level, and my vocabulary (which I have admittedly not studied very much) maybe a Grade 1 (native) level, but I know very little about the culture. For example, under what conditions can I use plain form? I know in stores they use a lot of Keigo (and I know pretty much no Keigo so I'm screwed, but I've already resigned myself to that unfortunate fact), so it is OK to use plain style back to them? Also when is it OK to use short forms like きゃ or じゃ? Basically any information on customs and respect would be helpful, but please don't misinform me, as it's very important to me to make a good impression when I go. Thanks.