Minimal Kindle
Unfortunately, this is a lost battle. A new update made the interface 1000x nastier (a terrible home screen is the default instead of the library).
Unsubscribe from special offers
Use this Amazon help page to find out how to disable ads in your device. It will cost you around $20, but it's so worth it. Your attention is more valuable than that.
Disable the cluttered 'Home screen view'
Go to Settings > Device Options > Personalize your Kindle > Advanced Options > and turn 'Home Screen View' off.
Delete books
Delete any book you are not planning to read in the next 6 months. Seriously, do it. You can always redownload them anyway.
Remove noise with collections
Create collections and add your books there. Personally I have one collection for each category / interest I'm currently pursuing. For example, my current collections are:
Fiction
Computer Science
Stoicism
I have scheduled time slots in my calendar to read a bit of each one of these collections. Besides it, I like to have a single book that I consider my 'current' book. I keep this book in a "Current collection".
Select the right filters
In your home screen, select the following filters:
Just downloaded items
Collections only
Ordered by title