One of the key factors for me when editing, is time — not time to edit, but time between edits. I don’t immediately see many problems in my writing until I leave a piece for a week or longer. When I return, the issues become clear.
My first step is to reread a section on the computer, but I never discover half of the ways I can improve my writing on screen. So my next step is to print out a copy and leave it for at least a day. I scribble over the printed copy and allow another day or longer before I reread the piece, yet again.
Once I feel I’ve done the best I can, I take it to my critique group who always find ways to suggest improvement. This may sound like a painful process, but the end result is worth the sweat.
At the end of a project, if I’m satisfied, I’ll do a final read of the entire manuscript. With my Tanzanian manuscript, I knew something needed to be revised in the plot, so left it for over a year and worked on other projects. This allowed me time to come up with a solution, while still productive elsewhere.
So my final advice: don’t be in a rush to send your work off to a publisher without first making it the best you can.