interfering ideas and promoting your book

Nanowrimo has its own jargon, mostly designed to promote in-jokes.  One such Nano phrase is the 'travelling shovel of death' and I used it in my 2014 Nano entry.  One that is more serious is 'plot bunny'.  From the Nano Wiki:

"Ideas are like rabbits. You get a couple and learn how to handle them, and pretty soon you have a dozen." --John Steinbeck
The plot bunny as illustrated on a NaNoWriMo trading card.
A plot bunny is a story idea that refuses to go away until it is written. The term's origin is unknown but is known to predate NaNoWriMo. Because plot bunnies tend to multiply quickly, the term is thought to be related to the oft-quoted John Steinbeck quote about ideas and rabbits.

I get the idea that too many ideas will ruin a book, at least if poorly handled.  To travel in too many directions is to circle...the drain.  What can be done with insistent new ideas while working on a specific subject?

Somewhere, William Goldman wrote about being under contract for a book but having an idea for another book that burned inside him and after consulting with friends, allowed himself one weekend to work on the new idea as much and as hard as he wanted before ignoring it to concentrate on his obligations.

K.M Weiland looks at the problem at Helping Writers Become Authors.

In this instance [of staring into a campfire], I walked away from that hour-long campfire with ideas for three new books. (And for those of you who have been asking for it, there is now officially a Dreamlander sequel in the works!)
This is not, of course, actually bad in any sense of the word. In fact, it’s totally awesomesauce.
But new story ideas can also be overwhelming–and seductive. When a new story is singing siren songs in our ears, beckoning us to new and exciting playgrounds, it can be downright difficult not to look a little bit distastefully at the trenches of our current work-in-progress.

...

My advice, when faced with sterling new story ideas, is to be patient. Nine times out of ten, the wisest and most productive choice is going to be staying the course on your current story.
Starting stories is easy. Frankly, as valuable as good ideas are, they’re also a dime a dozen. My having enough story ideas to last me thirty years is the writerly equivalent of my winning $3,000,000. Baby, I’m set.
It’s finishing stories that’s hard. Never be hasty in abandoning the work you’ve already put into an existing story. And never take for granted how important it is to instill in yourself the priceless habit of learning how to see a story through to the arduous end.

Weiland then offers suggestions on how to keep your ideas for later and improve them.  Personally, I Coggle them and work out some plans there.  I'm a lazy guy who has at least some ideas and mostly struggle with the finishing.  In this case, it means that spending thirty minutes to an hour to write down my ideas scratches that itch pretty well and it doesn't bother me for a while.  I also carry my commonplace book (it's a school-style notebook) most of the time or use the free version of Evernote on my phone to remember for me.  If my handwriting were better and I could be sure of reading my notes after a few months, I would stick to my comm... OK, notebook as I can fill a page any way I want with stick figures and drawings or text.  I haven't found software that is as comfortable for me.
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This author promotes her book with enthusiasm whether she is speaking to three people or a crowd of 9.

"I have to remember that even if just one person shows up, he deserves the same passion and enthusiasm I would give to a big group of seven people or eight people," said Massey, watching as a bookstore employee began setting up rows of folding chairs. "You just have to remind yourself that you're not going to be able to pack the room with half a dozen fans every time."