Ok, I'm here with (hopefully) the answers you seek. The ending is perhaps the most important part of the novel. No, scratch that, it is THE most important part. Why? Because all of your meaning, and all of the experience of the novel is crammed into this short portion of the novel.
Many times it's explained as the conflict "coming to a head", and that's true... but ignores additional questions regarding the size and nature of the head.
In thinking about stories, I go with the Act structure. I don't explicitly label my acts, but I know they're there. The Acts you're concerned with are those of the "main" plot. Every subplot has Acts too, but the main plot is what the story hinges on.
What is an Act? It is a major transition in the plot. The traditional 3 Act structure is used in most feature-length movies, so go looking for it next time. Right before the climax, the plot changes focus.
Think of it this way. No matter how you split up your Acts, 2 things usually (remember, "usually") hold true: the last Act, which leads up to your climax, is the shortest and fastest pace-wise; and after the climax, the last Act is over, and you now can have a resolution for the leftover bits in your plot. The first one is just adhering to the natural laws of human desire: you show us what we want (at the Act switch), and we'll want it badly.
So the concept of the last Act doesn't mean that you're cutting the story short. Quite the opposite. The conflict you put into the last Act will lead up to the climax, the most important point in your story. If you go straight to the CLIMAX from the previous Act- THAT'S too fast. The point is to give your audience time to prepare for the climax through the conflict and setup in the last act.
By having that distinction, you can know yourself where exactly you're going to start seriously setting up for the climax. Now, you should've been setting up all book long, but it's not till the last Act that you refocus the conflict towards that last struggle. This is where what will happen at the end will most directly effect the action in the plot. I mean... it has to! Just set up a conscious point where you will start on the road to the climax, and then build conflict appropriately till that perfect ending.
So the last Act is the "ending" - it contains the set-up of the climax and the climax. The other thing it should contain most of the time is a crisis. This is when the side of the protagonist has the chance open up to them where they could lose EVERYTHING they have worked for throughout the story. It's crucial that such a moment comes up somewhere before the climax. If it's an internal battle, make them able to go back to how they were at the beginning... challenge them. If it is a James Bondish sort of story, the crisis is where the villain has the MC in their clutches, and has the MC completely under their control. Then... bring on the climax.
So, how do you pull off a climax? Well, you should have mini "Act climax"'s at the end of each Act. However, the climax of the final Act is different in this way: the climax MUST bring about irreversable change. The change brought by the final climax CANNOT be undone. This is true in every story. It is the act of irreversability that makes a climax a climax, and brings meaning to the story. I mean... if it could go another way, why did the story end?
Remember, this is only the main plot's climax. You can still have connecting threads that can be left to start a sequel, but the book's inner logic must be satisfied. Learn how that logic works for any story, and you're well on your way.
Hope that helps

good luck.