This will be short.
When you're eating, your fork and knife, if you need to set either of them down, go across the edge of your plate.
Under NO circumstances should they hang off the edge of your plate like crazy legs.
The reason for this is that when someone comes by to remove your plate, if your fork and knife are properly posed, they will not fall into your lap when the plate is lifted up.
Secondly, properly positioned cutlery does not pose a dining danger for the people who might be sharing your table. Things left hanging are easy to accidentally hit. Imagine if your lovely dinner guest happens to knock your fork or knife onto her new, white, silk, Simon Chang trousers.
Elbows do not belong on tables until the meal is properly cleared. Your chest does not go on the table at any time.
Your napkin goes on your lap the instant you sit down.
Ask more questions than you answer. People like to talk about themselves. If two people in conversation remember these two things, the conversation will flow well and probably be very interesting.
Many people think that good maners are pompous and to be practiced by the well-to-do only. This is not the case.
Manners make you nicer to be around.
'Kay, I'm done.