You are different from most people who "would like to write a book someday." You decided to read this article, which refers to "your book" in the title. This means you have an actual book in mind that you want to write. This puts you into a very small, and very elite, percentage of would-be authors.
For whatever reason, you haven't done it. Let me guess: you don't have time. There are many other possible reasons, including getting discouraged by other people, feeling your book isn't good enough, or even getting started and then stopping because it wasn't turning out as well as you wanted it to. The easiest reason to fall back on, though, is you don't have time.
Guess what? You do have time. You can find 15 minutes a week to write your book. At that rate, it will take a while, but you do have the time. What you might not have is the organization you will need. Without organization, your 15 minutes will be spent going over what you have already done, instead of adding to it.
Here is your organization:
In your first 15 minutes, write down what your book is about, well enough so that someone else can get a solid understanding of what to expect when they pick up your book. This short description should be as close to cast in concrete as you can make it, because you will use it from here on out to keep yourself on track.
The following week, in your next 15 minutes, write down the chapter titles, and maybe a sentence or two about each one. This may take two or three 15-minute sessions, but do as much of it as you can in the first one. This outline doesn't have to be quite so solid, but it will be invaluable as you continue your sessions. Maybe down the road you will add, delete, or combine chapters, but that is for later. For now, just list the chapters as best you can.
Next session: Outline the main points you want to make in chapter one, or the characters you want to introduce if it is fiction. No detail, but enough information to guide you in the actual writing so you don't have to re-think it in future sessions.
Each session for a while: write about each point in order, or each character. This is the actual writing part. This is where you might start slogging, fall down, and lose hope, if you fall into The Re-writing Trap. Oh, it is a sneaky trap. You write something, don't like it, think it could be better, and re-write it. Blam, there go three of your fifteen minutes, and there goes your book.
Do Not Re-write While Writing! Even if you know you messed up a sentence or spelled a word wrong or could come up with something better, Do Not Stop! Get your thoughts down on paper about that one point or whatever small goal you have set yourself for that session. You can and will be re-writing the whole thing later anyway. Plus, by the time you finish, your re-writing will be very different from what it would be at the beginning. When you re-write after the book is done, you will be re-writing a cohesive whole, to make it all work together, rather than re-writing bits and pieces that you will later have to re-write again anyway.
The fact is that the first draft of your book will not be great, but it will be complete. Well done! Take a week off if you want. Then start reading, with a pad of sticky notes at your side. Print out your book and read it straight through, 15 minutes a week, and stick notes on it wherever you see something that needs changing.
When that is done, go through and handle one sticky note per week.
Repeat as necessary.
You will finish your book. Whether it is good, bad, or indifferent, it will be done. Chances are very good that it will still need an editor's experienced touch, or even another more experienced writer's flair with words, before it is publishable, but it will be done.
The only way to find out for sure is to decide when you will next have 15 minutes you can call your own, and get started. It's about time, after all.
Don Dewsnap has written three books part-time, all published. He is working with WriterServices.net to help authors achieve their book goals. For more information on how to actually, for real write, publish, and sell your book, go to http://www.thesavvyauthor.com/a>/a>