I also make a lot of notes on the pages. Here's an example of the notes on one page of the manuscript I'm currently revising. (R is the hero, T is the heroine.)
How does he look? (refers to the hero)
clarify/expand a bit
Where is he? (meaning, in the room)
How does he look now? Same?
See next page.
No change until T. orders her?
Speaking as if R isn't there - T still baffled
Imagine this times about 300 or more for a full manuscript. So you can probably also imagine that by the time I'm done, I've got quite the marked-up, cut and pasted, mangled-looking manuscript.
Then, of course, comes making the noted changes on the computer, until I have a completed second draft.
Then I print the entire manuscript again and go through it from start to finish again. At this point, I'm hoping all I have to do is polish and expand. (My initial drafts are always lean and light on description.) But I'm not surprised if I discover that I have more major fixes and adjustments to make, so I wind up printing and going through the manuscript from start to finish a fourth time, possibly a fifth before I feel it's ready to go.
Then, and only then, does anybody else get to see it, and that's my editor. Who will probably want more changes made, so the process starts all over again.
So to all those folks who think writing is easy, I say, typing is easy. Writing is work.