The first and most important rule of manner is kindness and consideration to others.
This rule never changes.The source of the rule is the Bible. This is the second most important commandment next to loving God.

Remember knowing what is right is only part of having good manners .It is the doing that counts.
So think of others first.
Do not be boastful, arrogant or full of pride,always exercise restraint ,Let your deeds speak for themselves.
Listen before speaking, never interrupt others while they speak.
Think of what you want to say before saying it out.