The main way to get motivated to start, or continue, writing your book is to put your butt in a chair. If you sit down, your brain will naturally start thinking about things related to non-physical activities– like writing. Writing is a mental activity, so you can’t be thinking about the laundry or yard work when you want to write on your book.
In order to have that best selling masterpiece you’re dreaming of, you will need to give it all of your attention– for at least a few minutes each day or week. If you only have 20 minutes a day, then use that 20 minutes to get something done. You will be 20 minutes closer to finishing your book!