Build a good relationship with your doctoral supervisor. Get together with other peers within the university. Isolation can be a real problem when completing a dissertation. Make yourself a realistic timetable, allowing rest and leisure periods. Write something down every day. Constantly remind yourself that completion of the dissertation is your goal, as it is easy to get bogged down in endless research and note-taking.
Develop an efficient filing system. Index cards can be useful and simple to access. Write down a chapter breakdown. Under each chapter heading, write a series of subheadings. Each time you sit down, aim to write something in one of these subsections. The act of completing even a paragraph will make you feel much better. The biggest hurdle is getting started.
Write down daily and weekly goals. Try to meet your supervisor weekly to discuss these goals; this will help to maintain your focus. If you are struggling to start, begin writing one of the easier subheadings. Keep your bibliographies and any tables or diagrams up to date as you go, as this can be an overwhelming task at the end. Break the work up into manageable chunks. Setting unreasonably high standards can be a reason for failure.