You've finally reached the end of your book, just remember, don't rush! Endings to books should make you want to say wow, not, that was a terrible ending to a great book. Endings take time, you can't rush through them like you do your chapters. You have to plot out your endings and beginnings delicately, making sure every detail is how you want it to be. Exposition is important in a book, you can't skip introducing some things, and, ending with some. Try to make your ending gripping, heart pounding, and as much as you can, a cliffhanger. Cliffhanger endings should only be attempted if you plan on doing another book in the series, otherwise it is very frustrating to readers. End with an ending you would be satisfied reading. Don't rush your ending, plan it out delicately, it is one of the most important, if not the most important part of your book!