Remember that kids’ joke. Q. How do you eat an elephant? A. One bite at a time. That’s a good rule for whatever project you undertake that seems to overwhelm you.
To make a daunting task seem more manageable, try breaking it down into small chunks. In the case of the book proposal, an overview; an analysis of the competition; how you could market or promote it; the chapter summaries and finally a brief bio.
Set some deadlines for yourself. A realistic one is 2 months, but if you are really enthusiastic about your book, you can do it in a week. Schedule an hour or two every day and treat it like you would any other responsibility. Meet those mini-deadlines for each section, and you’ll sail through it.
Nothing need overwhelm you – not even completing the book itself, if you make it into manageable pieces. It makes it easier to start, and to complete, a project and seems far less daunting.
A non-fiction book proposal just needs a brief summary of what the book will be about; why you are the person with the expertise to write it; what else is out there on the same or similar subject; and what you would be prepared to invest in it regarding book signings, lectures, promotions and travel.
Don’t swamp a potential publisher with too much to read. First see if he likes the idea and ask him would he like to read a sample chapter – give him the chapter headings and let him choose which one. If he is interested, he’ll ask to see more. Good luck.