Promoting my Amazon Books again

A few months back I was actively promoting my Amazon Books (Quotes Book and YouTube earning Book) using various ad Campaigns including Amazon's AMS ads, Google Ad Words, Reddit Ads, Facebook Ads, Goodreads Giveaway, LinkedIn Ads and Bookbub ads. But they are not much useful for my Books.  So, I stopped promoting my Books. Among all these Ad platforms, Amazon's AMS was performing better than others. But still, it was not making a profit.

A few days back, I have decided to promote my Book again.  Instead of spending all my time and money in many ad platforms, I have decided to stick with one particular advertising platform still I start making a profit from Book Sales.

As Amazon's AMS was performing better than others, I decided to start with AMS ads. I noticed that Amazon renamed AMS into "Amazon Advertising", and my previous campaigns were there. I just created new campaigns by copying the existing campaigns and started running with a small budget. I am planning to carefully tweak the ads continuously to make them profitable, and once after start earning money from Book Sales, I am planning to increase the Ad budget step by step.

 And, I have noticed that Amazon's new Advertising interface having many new useful features comparing to the previous AMS. Especially I like the option to see the reports for the date range. But still, the ACOS metric is not much useful. Because it is calculated based on sales price instead of the royalty amount.

I am exploring various options to improve Ad performance. If you have tried Amazon Advertising for promoting your Book, share your suggestions based on your experience through the comments.