You shouldn’t arrive too early. You shouldn’t usually arrive more than about fifteen minutes late
The general rule is you start talking to the person on your right for the first course and then you talk to the person on your left for the second course
And don’t forget 'please' and 'thank you' while eating.
- You just say please for whatever you want: ‘please may I have the salt or pepper,
- please could you pass the milk, or the sugar, for coffee', and then you say 'thank you' afterwards
There are certain topics which you’re supposed not to mention at polite events
and those are politics and religion and illness
If you’ve been to an event and it’s a very formal event and you have received a proper written invitation, then it is correct to write a letter of thank you afterwards.
Of course, these rules are mainly
for formal lunches and dinners. But as in any country, it is always a good idea to try to respect the people around you.