If someone takes the time to purchase a gift for you, to invite you to their home or to host you for dinner, etiquette says you must take time to write them a note thanking them for doing so.

One of the important things people want to know about elegant affairs, is which utensil to use at which time.  A quick tip: Use the ones on the outside and work your way in.

Present the younger or lower in status to the older or higher in status.  "Bob, may I present my son, Mikey.  Mikey, this is Mr. Smith." 

A condolence note should mention the loss, acknowledge the bereaved's grief, recount a specific memory of the deceased, offer condolences and offer to help. 

When you are talking to people in social settings, be aware of people who may be excluded from the conversation, either because of the topic, or the physical arrangement of where people are  standing or sitting or because of language barriers.  Find a way to draw them in.

When you want your invitee to bring a guest if he or she wants, you need to let your invitee know.  Address the invitation to your invitee and his or her guest.  If you do not know the name of the guest, your invitation should be addressed in this format "Mr. John Doe and guest."