Prologues

I will be the first to admit that I don't like to read prologues because many of the ones that I have read tend to be boring. Or, they are so great that the rest of the book is a let down because it doesn't have the same energy as the prologue. But I will never skip over reading one because to me, everything that's written in a book is meant to be read and I trust the author to have made it all relevant to the overall story. The only thing I skip over are the quotes at the beginning of chapters because, when I do understand what they mean, it feels like a spoiler for that passage.

Anyways, I don't write prologues myself. There are many people out there that hate them with a passion and I can see why, though the intensity is a little strange. After all, it's just ink on paper. But if you are writing a prologue there are a few things you might want to consider. 

If the prologue you currently have follows the same tone as the rest of the story, consider making it chapter one. While a reader will feel free to skip over a prologue, they won't ever skip over chapter one to make it to chapter two. Even if the point of view is different, if the tone feels the same you can often slip it in at the start. JK Rowling did this with her first Harry Potter book, The Philosopher's Stone. The first chapter happens ten years before the rest of the story, and follows characters perspectives that we will never explore again because Harry becomes the focal point. 

There are reasons to write a prologue, as well. 

Event earlier in history

Perhaps your story is about a war between rabbits because a century before one rabbit stole another rabbit's carrots. Instead of inserting it in the early chapters of your book you want to incite excitement right away and have a conflict from the get go. But this could easily become the situation I explained above where the prologue is better than the rest of the story. You have to make sure that the century later bunnies are doing interesting things as well. 

Different point of view

In your bunny war, perhaps you want to see from the opposite side to show the reader that both parties just want to finish this war so that they can go back to regular life. Or, there is a fox who has been waiting in the dark and will attack when all the bunnies are out in the open during a battle. So he slinks off, knowing that he will come back, eventually. 

Exposition

This one could get boring quite quickly. All it is, is an introduction of the world with the main characters or someone else so that the reader can get familiar with your setting. This way there will be less to introduce into the first few chapters. But unless there is a definite reason for why you have this, it should not be there. Having exposition just piled into a prologue is the reason that this literary device is getting such a bad rap. If it isn't interesting and mandatory for the story because it can't be told anywhere else, take it out. 

Foreshadowing

I usually don't like these ones. It's where you will get a snippet of the story at the beginning to add a feeling of foreboding because the main character is in an unclear-yet dangerous-position where they are fighting for their life. Or, going back to my bunny story, the main bunny is hopping through a finished battle, looking at all his dead comrades around him. But the problem I have with these is that you don't know what's happened, and you also don't know the main character, so it feels as though the author is taunting the reader. It's like they are saying, there's this really cool scene coming up but you can't actually read it yet because it's in the actual story. The issue here is that once I have gotten to the event, I have completely forgotten about the prologue. Therefore the prologue had absolutely no effect other than make me annoyed when I first started reading.

If you are adamant about writing your prologue, I have a few suggestions. Keep is as short as possible. A reader will most likely read a prologue if it is only one page, or one paragraph, rather than a full chapter length. It won't take as much time so they will skim it before getting onto the reason they bought the book: chapter one. 

Give it a different tone from the rest of the book. If it feels like the same as chapter one then it should be chapter one. Give the reader something they won't experience for the rest of the book because this will only happen once and it needs to leave an impression. If the space is going to be used, make sure that it deserves to take up that space.