I am a teacher who is studying in English. Maybe I can give you some informations about living with an Engilsh family.

Firstly,something about politness.(1) You should use polite greetings a lot even if you feel it's a bit excessive.For example:use "Hello" "Please" "Sorry" ect.(2) It would be a good idea make arrangements before dropping in to see friends in other host families.Because most of them have arrangements with their family or friends.If you do that without any arrangements it is not polite.(3)Don't stay indoors when your friends or classmates visit you.That's also not polite. (4)Your timekeeping should be good.

Secondly,something about eating. (1) Don't speak with your mouth full.In England,many people speak much less than in China when they're eating.You are advised to keep your voice down while eating. (2) Don't worry about eating on your own even if it might feel a bit odd to you.English people don't always have breakfast in the morning.You shouldn't feel strange. (3) If you go out to eat with the family.Going Dutch is the acceptable way of payment. This is very different.In China many people who go out to eat with their friends should pay for them.

Thirdly,something about asking. (1) Don't feel embarrassed about asking for something.The more you ask the more you'll get it. E.g. if you really really like to have some ice-cream,you should ask and then you'll get it.It's a good idea to do that. (2) It is advised to ask permission to do things even if it is the second or third time you're doing it. E.g. watching videos on their machine,using their washing machine ect.

Fourthly,something about other things. (1) Don't waste water.In their opinion water is the most important. (2)Smoking is less acceptable than in China. It is not advisable to smoke in the host family.Maybe just a few families will alow you smoke downstairs only. (3) You really shouldn't worry that they only wash the clothes once a week.

I hope this information is useful for you.Finally,I think you must remember one sentence that is "When in Rome do as the Romans do."