Q: deleting items in storage

You can see what your iCloud storage is used for and delete any unwanted content at settings > iCloud > backup & storage > manage......

It did not work. I want to clean up the storage and it is frustrating.

For example, I had downloaded the iPad manual for iOS5. I want to delete it from iBooks, but even following the instructions the item remains in the ibook shelf with a little cloud icon in the top right.

Your purchased media such as books does not use your iCloud storage.  You also can't delete items from your purchased list.  However, you can hide them from view so they will no longer appear on your bookshelf.

To do this, open iTunes on your computer.  Be sure you are signed into the Apple ID you used to purchase the book in question (in Store>Sign In).  Click on "Purchased" under Quick Links on the right side of iTunes, click on Books at the top of the page that opens, hover your mouse over the book you no longer want to see and click on the "x".

After doing this, close iBooks on your iPad by tapping the home button to return to the home screen, double-tap the home button, locate iBooks in the list at the bottom, tap and hold it until it wiggles, tap to close it, tap the home button again.  Open iBooks again and the hidden book should no longer be shown on your bookshelf (it may take a few seconds to disappear).