right from wrong

i am going to japan next year for 4/5 weeks to meet some freinds(student) i will be staying in their family homes and hope to travel just alittle bit with them,but i am just a bit concerned that i might affend them in some way(being just a simple kiwi)so i would like some help.i like to help people very much and do as much as i can for them. in nz i see the students and friends act abit different to how i think they might act at home in japan with their parents or friends,this sound like a stupid question (right from wrong) but to me it is important so any help in just the simple things people might do or expect would be great,thankyou

People will be grateful if you keep smile . Before arrival, let them know what you do NOT like to eat, something like cooked octopus, or some Japanese foods like Natto, or raw fishes.

If you do a search on something like "visiting Japanese homes" you should find a list of dos/ donts. Things like no shoes inside, obviously, and don't wear slippers on the tatami, change to the toilet slippers if available when you go to the toilet and don't forget to change back when you come out.

If you have to blow your nose, do it very discreetly.

Generally you are not expected to know the minute details of Japanese etiquette- if you behave politely and are friendly then you should be fine.