Hey [Friend's Name],

I hope you're doing well! I wanted to tell you about some social rules in my country.

When it comes to tipping, it's common to tip waiters and waitresses around 15-20% of the total bill. It's also polite to say 'thank you' whenever someone does something nice for you, 'sorry' when you make a mistake, and 'please' when you're asking for something.

If you're invited to dinner, it's nice to bring a small gift for the host, like a bottle of wine or some flowers. In my country, it's also important to take your shoes off before entering someone's home and to avoid talking loudly in public places.

I hope this gives you a better idea of our social customs! Let me know if you have any other questions.

Take care,
[Your Name]