When starting out as a writer, you have to think many steps ahead.
Book ideas are coming in, but you have to make sure that these ideas don’t clash.
You have to differentiate your ideas.
This means that you have to be diplomatic. You have to make sure that book 2 doesn’t sound like book 1 or book 3.
For example, in your debut book, the central theme is death. The book is out, and everyone feels the book, everyone feels the protagonist’s pain. Yay! Success! Bestseller!
Now, your publishers are pushing you to commence another book so as not to let the limelight fade.
You start the second book, but you notice that it is unsuspectingly revolving around death (again!). Then you start panicking, you can’t seem to outstrip the death extravaganza.
If you are planning on building a career as a writer, then please, before that first sentence is written, make sure you know exactly what your next book is going to look like, and the book after that.
You must plan 5 books ahead! Yes, Very crucial.
Lay out your ideas, long before you start penning that first book.
Make sure the protagonist in book 2 doesn’t share too many characteristics with the protagonist in book 1.
Make sure book 4 is totally different from book 3.
Another dominant factor is this:
sometimes you are not in the position (environment-wise, experience-wise) to write book 2 or book 3.
So, diplomatically, you can’t write book 2 or 3 at the time! Because you’re not in the environment, thus you lack the experience to write either book as your debut. So you must choose another idea that you’re conversant with.
Use what you have to get what you want.
For example, right now I’m on a book project; The Things That Stay Put.
Do I have hotter book ideas?? Hell yes!!
I can’t debut with them! because I still have a lot to experience, plus I’m much of the perfectionist.
I have about 4 massive ideas growing in the corners of my writerly mind. But if I’m not partially or fully living the life of the protagonists then I’m not touching them.
The Things That Stay Put is my experience right now, it is my environment, and mind you it is going to blow your mind (with encouragement from you all and hardcore persistence from my end).
So, I made the diplomatic choice to start with it, I played politics with my ideas.