Here are some interesting and helpful thoughts from a former professor of mine, Mark Gignilliat. An excerpt:
My dissertation examiners spent the last half hour of the examination talking to me about publication. I took their advice and made the changes they suggested (e.g. trying to stream-line chapters together, dropping one chapter and turning it into an article, etc.). They were very helpful; so, yes, I took their comments seriously. One of the best pieces of advice given to me was from the late Brevard Childs. While in St. Andrews presenting lectures, I asked him about dissertation publishing. His advice was, publish it, don’t fiddle with it and move on. Everyone knows what a dissertation is and to make it a magnum opus is to lose sight of what it is. Childs mentioned people who spent years polishing their dissertation for publication, and then that was it. They had given their creative energy to this project and were pooped. Again, I remembered Childs’ advice and didn’t do too much beforehand other than cleaning up.