Summarize this article in one sentence.
A good prologue is usually no more than three to four pages total. Read over your draft and trim it down. Remove any details are are not necessary to the overall story or nice to have. Keeping your prologue short and to the point will make it that much more effective and ensure your reader stays engaged enough to move on to chapter 1. The pace of the prologue should be quick and brisk. Avoid over explaining something or giving away too much information to the reader, as you will have an entire novel to do this. You do not need to cram the prologue with information that might fit somewhere else in the novel. Keep only the essential details. One way to check the pace of the prologue is to read it out loud to yourself or to someone else. Mark any run on sentences or awkward moments in the draft and work them over until they sound smooth and to the point. Once you have edited your prologue, you should place it in front of your chapter 1 and look at how it fits. Does it feel like an engaging start? Does it contain any information that is also in chapter 1? Does it strengthen the novel overall? Your prologue should be strong enough to stand on its own, separate from the novel. It should almost read like a short story, with a contained story line and a conflict. However, unlike a short story, the ending of your prologue should remain open. It can introduce a conflict that will be resolved or addressed later in the novel, leaving the reader wanting more.

Summary:
Keep the prologue short and to the point. Make sure the pace is fast and engaging. Look at how the prologue fits with the rest of your novel.