It can be very helpful to create a blog or journal to help you through the process. You can write it in longhand in a blank book, or keep it on your computer. In her wonderful book WRITE AWAY!, Elizabeth George shares entries from journals she keeps for each book she writes. My preferred blog host is Word Press. They are easy to use, have terrific customer service, a variety of customizable templates, and they’re free.
The only rule about journal entries is to date each one. That way, you can refer back and keep the entry within context. There will be many ups and downs on this road, and it’s helpful to look back as you’re moving forward; see where you’ve been to help you get where you’re going.
It’s a great way to play with characters and ideas. It’s a wonderful way to explore tangents that might not make it into the book, but help you flesh out your characters and situations. If you keep your journal in a notebook, you can tote it around with you and make entries whenever you’ve got a free moment, then take it back to your desk and integrate the material into your WIP.
You might want to write before you start your work, as a warm-up. Or you might want to write after you’ve completed your day’s work. In either case, daily entries will help you in the process, and will help you once you’ve finished.
Don’t publish excerpts from a WIP online. First of all, you only want your best, most polished work out there. Second, many places consider material online “published”, and thereby, you’ve used up your First Rights. If you want/need feedback, find trusted readers and swap manuscripts. Don’t send a raw manuscript out into the public cold.