By the time you start to write the first draft of your dissertation, you will probably already have accumulated a wealth of notes, scribbles and ideas.
Planning is essential, but do not be hesitate to draw up new plans whether it is a brief abstract of your dissertation as a whole, or a detailed breakdown of a particular chapter.
Prompt revision is easier than letting things drift, and you should do it while the advice of your supervisor is fresh in your mind.
This will also avoid building up a backlog of work that needs to be revised, which can be discouraging.
As you continue to write the main chapters of the work, you may find that your initial plan has changed.
This means that when you have completed the chapters that form the main body of your dissertation you can return to the proposal and revise it as much as you need, to form the introduction.
When you hand in this draft, you should arrange a tutorial to receive your supervisor's verbal or written comments and suggestions on how it may be improved.
You may, for example, produce a draft introduction setting out the issue, together with a literature review which covers what, if any, treatment of the topic has gone beforehand.
This may be more than one chapter, but should certainly be written in sections.
This should include previous work done on the field of study and anything that you consider to be relevant to the hypothesis or research question and to its investigation.