A prologue is pretty self explanatory, but not everyone uses them in the same way. Some people use it to just give a little backstory to set up the main story, I've seen a few people show a scene that will happen much later in the story, more like a preview almost (personally never understood that one), some people show a major historical event, or a history of the world. How do you personally prefer to use the prologue of your story?
I like the
Dragoon approach.
If you don't understand the reference, there's an anime back from the 90s called
Ryuki Densho, or
Dragoon in America. It was awesome cheese with really terrible stock lines. It's also softcore porn.
The prologue starts at some distant scene (that we never get to see, because the anime ended prematurely). They are talking about launching the dragoon, a dragon-shaped mecha housed and control by a (naked) girl named Mei. Her eyes glow as she controls the mecha, while herself having lost control of her mind and memories. She is opposed by a more experience verson of the male lead, Seidon. Seidon lifts his sword and charges, and the music swells...
Then we flash back to weeks or months earlier. Mei is on the boat to be delivered to people who will erase her sense of self and use her as a weapon. The sailors talk about "expensive cargo" and "sampling the goods." Mei screams as they try to molest her, and her eyes glow. Her clothes are ripped away, but the radiation from her power does an Indiana Jones face burning to skeleton thing. The next cut is to Seidon training in a snowy forest. Swinging his sword, he makes a small gust, using a sword technique. It is here that he finds Mei's naked body, covers her, and takes her to his cabin (after initial perversion of touching her breasts trying to lift her).
I think a good prologue should try to build hype for a show. An okay prologue leads up to something that is backstory to characters, like a childhood story for the female lead in Clevatess (which awesomely subverts the norm by having her senselessly killed in the first act). And a bad prologue deals in characters that have a secondary connection to the story, who only show up after several chapters pass and you forget they were mentioned (
Wheel of Time novels do this, having the even more egregious problem of incredibly long prologues). I am ashamed to admit that my second novel
Town of Winter had just such a prologue. But I tried to refresh the memory of the audience.