As already indicated, the most important thing you can do, before you start "making it look like you want it" is to find a publisher, or a printer/binder, that might be interested in doing the final production for you, and find out what is acceptable to them.
Many of the smaller houses will accept small jobs as Word files, and unless you have something really exotic in mind, there is no reason you can't make it look *any-way-you-want-it-to in Word. All that's required is that you learn how to use Word instead of just typing in it. (I would suggest one of the recent one or two versions of Word, if this turns out to be an option: Word 2000 or later(?).)
* The things that the "pro" programs can do, that Word doesn't do well or that are difficult to do in Word, likely are things you won't think of doing if you try to do the layout yourself. (Fine tuning of leading and kerning, for example, to eliminate "rivers" in the word breaks, and to manage widow/orphan control, etc.)
While you are doing your research on the production requirements, I'd suggest that you go ahead and do the writing, with each chapter in a separate file, consistently named so that you can easily know which is which. Any graphics/artwork you may want to use should also be saved, preferably in a separate folder to go with the chapter in which it will appear. Study up on how to create a "Master Document" and how to get your Table of Contents into it, or in an "Intro" chapter. Create no more than about 5 or 6 paragraph styles, with sample paragraphs in each style that you can use to show a layout person what you have in mind. Select not more than three typefaces (fonts)that you might use, so that your layout person has an idea of what "look" you want. One font will be for everything except specific, and limited, special features. Chapter and section titles sometimes use a different font. Quotes and/or comments, maybe another, but be very careful about being overly creative with them.
If the layout person ends up being you, all you'll have to do is apply the styles and insert the graphics and you'll pretty much be done, if you've set them up right. (But don't forget to have at least two other people proofread it before you go to print.)
If you really feel the need, go ahead and make a separate folder with "formatted" copies of all your chapters, but do keep the plain ones just in case.