I look for resonance, with the rest of the story, and I do my best to see what the reader will expect, and deliver that.
I have mentioned in other answers I am a discovery writer, but I keep my endings in mind. Anytime my characters take me in some new direction that means my current ending won't work, or is boring, if I feel I must keep the changed direction, I stop and write a new "sketch of an ending". The new sketch I just wrote, probably the last since I am 90% done, is about 400 words long.
It has no "prose" or dialogue, nor is it an outline; it is what in film would be called a "treatment", exposition of how something unfolds. Like a treatment it can be used (like an outline) to write the ending, which could be 20 times longer than the treatment; it is just a guide to writing the ending.
The reason I choose this ending is because I can include some resonance with two previous events in my story, including the inciting event; meaning the ending bears a strong similarity to the early (massive) defeat of my protagonist, but now she has many years of training and, though she risks her life, she can be victorious.
That was unintended, after re-reading my story so far as an edit to cut waste, I realized I could have an ending that echoed these earlier incidences, and I like that kind of ending.
The second factor is what your readers should expect. If your MC is supposed to be the paragon of some skill (battle, magic, seduction, confidence games, corporate finance, card shark, pool shark, sharpshooting, running, detective work like Sherlock Holmes, super lawyer, whatever), then even if they have sworn off using that skill, the reader expects them to USE that skill in some way to finally triumph. Perhaps not in the on-the-nose way: A world class poker player may not be playing cards in the finale, but he might bluff his way to victory, or know his opponent is bluffing, because he thinks he has spotted a tell.
The reader expects your hero to be a unique person in your story. Not necessarily "unique" in the sense of inventing a new super-power, just unique relative to the other characters. They also expect you gave your MC these unique attributes for a reason. Perhaps that is what gets her in trouble in the first place! But it helps the ending to be satisfying if her unique traits figure in to the ending, help to bring it about, even if they were what got her into trouble. (e.g. she is a math wizard and card counter that used her skill to cheat at cards in casinos, and got in trouble with gangsters, but the same skills help her escape and bring them down.)
A satisfying ending doesn't just wrap up loose ends and reveal the mysteries of this novel (or episode), it connects to important events in the rest of the story.
Once you HAVE your ending, you may want to go back over your story, and see if there is anything you can tweak to create such resonances, or make them stronger.