1) People judge you at first by what they see, so particular attention should be paid to your personal appearance.
2) Using a Handkerchief
Always carry a clean handkerchief. Do not use it while it is folded, and do not fold it after you use it.
3)Spitting
In the West it is considered very impolite to spit, even upon the street.
4) Smoking
Smoking is very prevalent(普遍), both by men and by women. If you are a guest in a home where no others are smoking, it is better to refrain(忍住） from smoking, you may say, "Would you mind if I smoked?".