I just read an article entitled How to write whether you feel like it or not by Joe Bunting.  I read this article because this third book is not coming easily.  I mean this book is actually making me work.  That's not fun.  I'm retired I don't want to work anymore.  With my other two books, I watched a movie in my head and simply had to write it all down as I saw it.  Easy breezy (I jest...it took me two years for each book) 
So the article offers suggestions...take a walk,schedule writing time and stick to it...maybe write for a local newspaper or an article for a magazine(maybe a blog) .  Find a new or comfortable writing nook.  I have a comfy chair that I'm writing in right now, Thistle Dew was written in my bed, Men in Ts on the sofa in the TV room...both locations explain why the books took two years.  Hang out with other writers...This one is my favorite.  I attend weekly critique meetings, monthly writers meetings and host writers retreats a few times a year.  The creative energy is amazing and I am most productive in the 24 hours following a meeting. 
So here I sit,  waiting for my characters to speak to me, writing to you.  Thanks for listening...I mean reading.  Do you have any suggestions for me....to get back to writing the book?