Linear revision kills
Many writers jump into revision like a swimmer into shark waters. They wade through their draft again and again, focusing on different elements, and slowly they drift out deeper and deeper, moving in circles, making deeper changes without a proper reference. Then the sharks show up and guess who's on the menu?
Whether those sharks are the editors or agents who send out polite rejection letters, or the Gollum in your head that tells you the task is hopeless, linear revision is bound to kill you sooner or later.
It's madness, but there's method in it
Not all is lost! Time to stand up straight and learn how to master revision. The first stop is the posture clinic, aka the post-draft outline.
What is this, exactly? (Or, if you're a "pantser", the dreaded O-word might make you cringe.)
For me (an outliner) it is an outline, but if you prefer to avoid outlines altogether, consider this an exercise.
Go through your manuscript and try to identify distinct chunks of your story. These are not necessarily scenes or chapters. They are segments, anywhere from 200 to 2000 words or so, where your story takes on a unique cadence and shape. For example, if your scene is a dialogue between conspirators overheard by your POV character, followed by your POV character's introspection while she rushes down a dark alley to warn her father about the plan to kill him, these events would stand alone.
Develop a numbering system -- I use decimals to show divisions. For example, if I'm in chapter 1, the segments will be 1.1, 1.2, 1.3, and so on.
Go through from beginning to end. If one of the sections is particularly long, don't worry, but do see if there is an inflection that breaks it up. For example, if you have a long conversation in one passage, have a look. If it starts out with an exchange on the history of the world, then someone interrupts with a recent event that changes the topic, then this inflection divides the action to make the two parts unique segments.
Going over your whole story and dividing it up will allow you to appreciate where certain segments wander. Imagine each segment as a plunge under water. If you keep pulling your reader into the depths without giving them a breath, they're going to politely swim away to another tour guide. Similarly, if you pull them under for a long time once in a while (which you should!) then it had better be worth the view.
Once you have your manuscript divided up, go over and ask what each segment does -- how it helps the story as a whole. Cut, develop, re-write. Be honest. Be brutal. Be thorough.
Most important, watch out for the sharks!