Sorry there is not a guide for deleting space in storage.
This is a recent thread, starring yours truly.
http://forums.androidcentral.com/as...t-gets-labeled-other-storage.html#post4252741
You can tap Used Space in Storage, see Hidden Files in My Files - Menu.
One thing you can do is move/copy photos and video's from the DCIM folder to pc, I do all the time. (old fashioned)
You can also use the Samsung Kies pc program to sync, copy and back up most files. but also sync things your Samsung account - Scrapbook and S-Note files for example.
If you think you have a serious unidentifiable storage issue hogging a few GB's, I learned you can dial *#9900# and Delete dumpstate/Logcat files without harm. It's very rare that you would need this and @rukbat here could explain how this happens much better than I.