Attention to marketing, covers, sales, methods, and a million other things, is fine, as long as the book actually gets written.
As many books are being written today, the number which are partly written, never to be finished, is greater.
Focus. Plan. Write out a plan. Write the book.
I wrote a book, Write Like A Ninja which is directed at one specific goal:
Writing a nonfiction book from beginning to end. Getting it done.
The title was chosen not as a gung ho marketing gimmick, but rather to indicate the very real need for you to view your desire to write a book in terms of a mission.
No bullshit. Mo meandering. Getting it done.
Write Like A Ninja does not deal with marketing, covers, how to sign up for KDP, or the many other things which are distractions for the person who is not doing the one thing which really counts:
How to go from idea to finished.
The meat of writing is...writing.
If all you had to do was concern yourself with making a cover, the deal would be done a thousand times over. You would do it yourself on your own, or using the Amazon cover creator, or you'd pay someone 5 or 10 dollars and be done with it.
You don't really need to pay someone to tell you how to sign up for KDP, do you?
The difficulty people face in the process of writing something from beginning to end does not involve anything other than writing.
Deluding oneself into paying attention to all the other things you will have to do is stealing time from oneself.
Write Like A Ninja lays out a plan of how to write a nonfiction ebook from idea to finished.
That is what will take the majority of your time.
Sure marketing can take a lot of time, but honestly, it's the writing that holds people back.
If you haven't finished writing your book, the idea of which you might have written on the back of a paper napkin, it's not because you have not yet finished all the marketing work, it's because you haven't written the book.
Write Like A Ninja not only serves to give a plan which ensures constant action bringing you closer to being finished, it also serves as an excellent example of finding your voice in writing.