It's been 4 years since we last did sleep training (and then, we didn't approach til 6 months). Our little one is nearing 4 months and we'd like suggestions on gentle methods. I'm ok with general fussing, but we won't do CIO. Was there a book or website that helped you?

Right now, we nurse to sleep and roomshare. We will still roomshare, but I'd like to take nursing to sleep out of the equation (in case this detail changes the book/resource you'd recommend).