Now that I’ve published my first novel, To Hunt a Sub, I can say from experience that writing it and editing it took equally long periods of time (and marketing is just as involved). After finishing the final rough draft (yeah, sure) and before emailing it to an editor, I wanted it as clean possible. I searched through a wide collection of self-editing books like these:
The Novel Writer’s Toolkit by Bob Mayer
Self-editing for Fiction Writers by Renni Browne
The Marshall Plan for Novel Writing by Evan Marshall
…and came up with a list of fixes that I felt would not only clean up grammar and editing, but the voice and pacing that seemed to bog my story down.