How do you maintain a solid work rate?

That sometimes is the problem. Part of me thinks that art piece is only done if it is done to as close to perfection as I can do it. Now that I make manga sometimes I revisit pages that I have already done and new details to them. when I was working for the contest entry I had a deadline to worry about. So I somehow was able to not seek so much perfection. I just drew one page at a time and if I liked I kept it. At the end I still had a week+(?) till the deadline. But I felt that my pages already told the story I wanted to tell and there was no point in adding anything else. So I decided that it is done and submitted my entry.