What Every Writer Needs to Know About Plot and Structure, Part 1

Let's start with classic story structure. Basically, this covers myth, legends, fairy tales, epics, etc... It has been repeated many, many times.
(Star Wars is famously known for using this.)
According to Jospeh Campbell, many plots contain the same elements and structure. You may be familiar with the Monomyth or Hero's Journey. He lists 17 stages of the monomyth, including:

1. The Hero is called to adventure
2. The Hero Refuses
3. The Hero Receives Supernatural Aid
4. The Crossing of the First Threshold
5. The Road of Trials
6. The Ultimate Boon (hero completes the quest)
7. The Crossing of the Return Threshold
8. (The hero is a) Master of Two Worlds

Then there's Vladimir Propp's 31 functions (his is my personal favorite).
For you Harry Potter fans out there, I believe J.K. Rowling used each of the 31 functions repeatedly in her series. If you don't believe me, or would like a challenge, the 31 functions can be found here.

These are based on classic storytelling and archetypes that, according to Carl Jung, every human being has a connection with. Nina Munteanu has an excellent article on classic story archetypes.
She also has an article where she takes The Hero's Journey and gives multiple examples in her Journey's Map.

The pros of classic structure: it has the tools for a perfect story arc, something that settles nicely with everyone, happy ending and all.
The downside is that it's been done millions of times. Readers want something fresh. The trick is to use elements of classic storytelling, while putting your own twists and turns, red herrings, and other goodies into your writing.
Which will be covered in part 2, part 3, and part 4.