The best way to get a new book written is, of course, to rearrange all the items of furniture in your study. And you absolutely have to do it single-handedly. Even if your desk is a huge, old wooden beast, and you have a massive filing cabinet full of documents, you just have to move everything on your own. No - don't get anybody to help you. It's the only way to write a book. Definitely.
My other tip is this: once you've rearranged everything, make sure you leave several items of furniture OUTSIDE the study. Perhaps leave them in the bedroom, the living room, the bathroom - anywhere that they don't belong, and anywhere that they will cause most disruption.
This way, the study will seem much bigger than it was before. There'll be plenty of space to think, to write, to swing your arms around, to practise your off-drive and your bowling action. The rest of the house might be a touch cluttered, with tables and boxes hidden in awkward places (like the middle of the room), but that's OK - you're writing a book, remember, and nothing else matters.
So move everything around (also - try to strain a couple of muscles and drop heavy items on your foot while you're doing this), leave several things in the wrong place, then get back to your desk.
It's a joy.