Japan is an amazing place to visit, but it can seem like a rather rigid culture. However, there are two sides to everything. The modern and the old. But there are certain etiquettes you should follow if you don't want to appear to be an obnoxious traveler.
Food and Drink
1.) Don't eat/drink while walking. However, I have heard from some people that this is kind of outdated?
2.) Don't leave chopsticks pointing up in your food; don't pass food from your chopsticks to another person's chopsticks; don't pour sauce on your rice (also possibly outdated?); get food from main plates with the fat ends of your chopsticks; leave chopsticks parallel and pointing left on your plate when you are done.
3.) If someone pours you a drink you should reciprocate; don't pour your own drink.
Gifts
1.) Give a gift when you are visiting someone for dinner, etc. or staying with a host family.
2.) Don't give gifts that come in four's or nine's; the word four is similar to the word for death and gifts of nine are considered unlucky.
3.) Offer and receive the gift with both hands (or most things really)
Miscellaneous
1.) Don't blow your nose in public.
2.) Don't talk on your cell phone on the trains or in public places such as restaurants.
3.) Don't wear your shoes inside; usually slippers are provided.
4.) Wear the special bathroom slippers when going to the bathroom.
5.) No tipping is required.
When I was traveling in Japan with my family we had my sister to guide us, who had been living in Japan for about half a year, so we didn't make any too big mistakes. There were a couple incidents though...
I was walking to the bathroom at the hostel I was staying at, and it was late at night. I was still extremely jetlagged and could barely keep my head up. I fumbled for the light switch and finally got it. I went in, did my business, and when I came out I ran headlong into a Japanese lady. She looked at me, and then my feet and gasped in horror. "@#$%$^%^&!" She exclaimed. I had no idea what the matter was and smiled politely. She scurried off, no doubt to tell her friends what she had seen the stupid gaijin do, and I stumbled back to my room. The next morning I mentioned what had happened to my sister.
"You did what?!" She screeched in my ear.
"Really, Liz, it's like 3:00 in the morning for me so please keep it down."
"You wore your regular slippers into the bathroom?"
"Yeah, why? Are there special bathroom slippers or something?"
"Oh my God, you are so oblivious." She sighed, covering her face with her hands, "It's so shameful!"
"Whatever, I'm going back to sleep."
