I have found a lot of people ask the same type of questions, ultimately they think there is a trick to taking a shit book - doing some magic - and it suddenly becomes a top seller, then they do that over and over and become rich.
There is a business process you can use and things you can do to maximise income, but ultimately it has to start with a high quality book. Else it doesn't matter what else you do it simply won't sell. If your book is shit, by which I mean is not measuring up to your competition in the ways the reader expects, spending months deliberating a pen name won't matter. You can always go back and change things once a book is uploaded.
If you have the skills to do that then great. Do it. If you don't accept you are going to have to pay others to do it for you and if you don't you will have a shit book.
Write it ASAP, write it well and get it out as fast as you can. If it sells go back and scale marketing etc and turn it into a series. If it doesn't go back and start again. The faster you fail the quicker you will achieve success. So fail fast!
Almost every tip you will get on here is about IMPROVING sales. If you don't have that many sales to start with it isn't going to be worth the effort to implement them. It is a bit like me buying a $1000 pair of running shoes to improve my speed. I am so crap at running it isn't going to matter. But for Usain Bolt small % improvements make it worthwhile. Similarly why buy loads of reviews and other marketing things if the book isn't selling? Unless you are prepared to spend serious money on marketing you cannot sell a shit book. Your better off spending the money on making the book better or creating another book that does sell.
To measure quality head to the Amazon website and look what the top books in your niche are doing, how many pages, does it have images etc? Then understand you are going to have to do it better. Look at the price point. How many reviews does it have, it's quality of writing, how is it structured etc. Then ask yourself can you do better?
If your book isn't up to the same standard or beyond no matter what you do you will not sell many. Because they are setting the benchmark for your niche.
The days have gone when you can release any old crap on Amazon and it will sell, there are too many self publishers now, so your book will get lost in the maelstrom of new releases.
Your better off producing 1 high quality book that sells well than 10 low quality ones that don't. Then you can play the numbers game with something that sells and make real money, rather then putting all your efforts into something that doesn't sell well.
The trick is creating a high quality book that sells and even if you do that there will come a point where you are simply treading water to maintain your income unless you scale. The higher the quality the book the less you have to tread water. Do it right and it will start to sell off it's own own back. Then scale marketing just like you should successful books.
I am going to be starting another joint venture soon. Where if you create the book I will sort the sales for you in return for a minority %. The book can be in any niche, though I have the most success in kids books and I will only have one condition: that it is of high enough quality that I can achieve sales with it. Feel free to PM me if you wish to discuss that further.