I worked on a book about Node.js and Backbone.js last year as a side project. Keeping motivation is easier if you have some rythm. For the book, I wrote mostly

I worked on a book about Node.js and Backbone.js last year as a side project. Keeping motivation is easier if you have some rythm. For the book, I wrote mostly on Friday evening and Saturday/Sunday mornings. From publication to first sales, it took much time. So, in that time, I was missing mostly feedback, what others think about my project. For my new sideproejct, a meetup group about Arduino, I find it great to have regular feedback from a "known" audience.