Now, to get into some of the nitty-gritty of how exactly this self-editing thing works.
Can you trick yourself?
If you can't, your first step in self-editing will have to be figuring out how to trick yourself. (Don't worry; there are many tactics different people use, and I'll be bringing them up in this series.)
When you read something you've written, you see what you meant to do—the "treats," as it were. To edit and revise it appropriately, you must trick yourself into seeing what's actually there.
Not what you think is there. What's actually on the page.
On a copyediting and proofreading level, there are several options available for tricking yourself. All of them are tedious, but they work pretty well, particularly when you combine methods. (If you want to know something now, see an old article I wrote here—but on this blog, I'll be more thorough.)
Not that those methods do you much good if you don't know how to copyedit or proofread (or if you're particularly dyslexic), but I'm going to assume that you're honest with yourself when you evaluate your ability. (And if you can't edit or afford an editor, have you checked out the possibility of crowdsourcing?)
With big picture editing, however, tricking ourselves is a bit harder. We have to see the scenes and plots as they actually fit together, not how we want or meant them to fit together.
For doing this, some writers use note cards, one per scene, then organize those cards for each of the different things they're checking and take notes about what needs fixing. (Example: a story with multiple POVs could have note cards arranged for the author to see how many of each POV there is and where. The author could also then rearrange them to see how many cards dealt with a particular, say, romance subplot, and where those scenes fell, to make sure they were well-spaced.)
Those of us with Scrivener can also make use of the program's keywords to view such things. Some just take a notebook and read through the manuscript multiple times, checking different aspects each time.
Some folks do a single read-through and leave it, but the ones who pull that off tend to have more experience with the entire "reading and writing stories" thing.
Though Scrivener's keywords can be incredibly handy for making sure a minor character didn't mysteriously vanish for half the book, I generally do my scene-by-scene analysis with physical 3x5 note cards. I use a variant of methods I've read from Holly Lisle and Shanna Swendson, as I recall.
The main unique thing I do is that I don't use colored note cards to indicate how much work a scene needs (green for next to none, red for scrap and redo, etc). Instead, I put all my scenes down on white cards, then take highlighters or markers and mark along the top edge of the card. (So when you take the stack, flip it so the text is facing you for you to read, and the color shows on top of the stack.) I also make a "Key" card, with the colors and what they mean.
Afterwards, for organization, I might hole punch them all and misshape a paper clip to use as a ring. More often, I take a small check envelope and write the book title on it, then stick the note cards inside.
I'm being intentionally vague here about what to check, because that'll differ depending on your type of story and how you write it, but I'll try to get more into that later.
Can you trick yourself into seeing what's actually on the page rather than what you want to be there? How do you do it?