I guess the best way to start this series is with the main character that shows up the most often in archetypes - the hero. Now this hero doesn't have to wear tights, save people in a single bound or even fight a villain.
This is going to take some participation, so before reading think of a main character - movie, book, your own WIP, and check off the list as we go through (if you need some ideas think Star Wars, Harry Potter, fairy tales, Pride and Prejudice, any comic book hero, etc.).
A hero often has a wound - a scar even - that cannot heal. This does not have to be physical, and in contemporary literature, it's often more mental and emotional than physical. Along with this generally is a traumatic event that will catapult them into their call. This can be a death of a loved one, but doesn't have to be - the disruption of social status, expectations, loss of trust can serve this purpose as well.
A hero has a special weapon. In magical and supernatural settings, this will be a weapon only they can yield, but in contemporary times, it can be a wit, wisdom, perspective, etc.
A hero will start to prove themselves in some way as they work to answer the call that they initially started out on - win a small battle, show more inner strength than they thought they had, rise to the challenge issued when they doubted.
A hero also will make amends, restitution even, for something they have done wrong or something their ancestors did wrong. While the hero generally can't right all the wrongs, he/she can set the path to let the healing and redemption begin.
Some of my favorite archetypal heroes are William Wallace, Simba, Elizabeth Bennett, Belle (Beauty and the Beast) and Val Jean.
Who are some of your favorite archetypal heroes? Where there more than you realized? Have you been writing this archetype? Did you know it?