Hi. I am currently in the process of writing my dissertation. Almost done. My only advice is to be patient. The initial motivation will eventually be gone and it will be harder as you progress but not because the material will be more difficult. it is just a long program.
Just take it one module at a time and do not look to much past that point. Otherwise it will drive you insane. You have enough time to complete each module if you are diligent in your studies. You can even take a week off here and there but do not make it a habit.