The Wadsworth Atheneum.
A very common every day occurance that rarely happens in the correct way or not at all. How many of us have been in the awkward situation of not being introduced to someone by a friend or co-worker? It happens much to often and needs to be rectified.
When making introductions you are supposed to introduce the least important or youngest person to the more important or older person. And you are supposed to introduces men to ladies. Never the other way around. Now I know you are probably thinking "Well that's a lot to remember and pretty antiquated. So, no thanks." But truly it is in your best interests to learn. It's good practice to just say the name of the important person first then follow with "this is" then name the second person.
Example: "Heather, this is my friend Colbi."
Of course there are many ways to introduce someone besides saying "this is" but you get the picture. And don't worry too much about the importance factor or anything like that. If you do it backwards it's fine at least you are getting your guests aquainted with one another.
Remember etiquette is about making people feel comfortable in social situations. And nothing will make a person more comfortable than knowing everyone's name.