Few parents care about what others think of their badly behaved children. So if you teach your children the most important basic manners, you will do both kids, yourself and others a great service.
First Say thank you
Even from a very early age, one can easily teach them to say thank you if they get something from others. It's a basic courtesy that all children should be familiar with.
Second Hold table manners
The manners a child learns at the table will usually stay with them for the rest of their lives. So teach them that they should not make noise while eating, and that they must sit properly, so food won't be all over the place.
Third Opening gifts nicely and say thank you
The youngest are often very exalted when they have birthday, but it is good to teach them how to control themselves a little, so they do not tear the paper packages. Tell them that it is not just about getting all the packages opened as quickly as possible, but that they should show givers that they appreciate each packet they receive.
4th No profanity
It is not very flattering to curse. But children will of course their the parents' reaction to different words. Do not laugh and tell the child that you are familiar with the word, but it is not one that they need, because it is not pretty.
5th No to Bullying
Children like to tease each other, but as parents you must help them find the limit beyond which it is bullying. Bullying is not okay and it should be emphasized from the very earliest childhood.
Children can be a bit clumsy and have fast movements. But if they walk into other people or fall over things, parents should teach children to say sorry.