A Great Post -- Strategies for Successful Dissertation Completion
Here is an extremely useful post on the Crooked Timber blog by Eszter Hargittai, with helpful additional comments by readers, on Strategies for Successful Dissertation Completion. I added my own comments on how to choose a dissertation advisor.
I would also add a small addendum about the reading and literature review stage of your work -- when you are reading, don't just underline or put stars next to great paragraphs. Take the time to do a little free writing about how the article or book you're reading ties in to your planned work, whether you agree with it or not, what questions it brings up, and any other floating thoughts that come to your mind. You'll be so glad later you did this.
In addition to this, free write every day, even when you're at the beginning of the process. You'll be surprised later how much of what seems like drivel can be useful in jumpstarting the writing of the final product.