- Writing a book is a huge undertaking - make sure that you have the time to do it.
- Find a good environment to write the book in - if you have kids/pets/others that will interrupt you, try to find somewhere else to do the writing - Marcus Hammerberg (the co-author of Kanban in Action) wrote his in coffee shops, with the side effect that he gained 10lbs, so factor that in.
- Try to pause on blockers if you can - time spent on coding/writing does not always result in the equivalent amount of book being produced.
- Check what the tech landscape for your book's subject is like - if it's very fluid then plan around it - since I started my book, Node.js was forked to create IO.js, Node Webkit was renamed to NW.js, IO.js merged back into Node.js, and then Electron emerged on the scene and now overshadows NW.js (which is ironic given that they have something of a shared history).
- Keep your editor informed - I've had quite an eventful 18 months and it helps to let them know what's going on in your life.
- Writing a book is a great feeling when you see your name as a published author.
I think the one takeaway is that it is like doing a dissertation whilst also doing a job - ask yourself if you can commit to that. If you can, great. And find the right motivation too, because you are putting at least a year of your life into this project.