With Gnome 3, the keyboard shortcut to delete a file was changed from delete to control + delete. I will show you how to change it back to just delete.
Open dconf by pressing alt + f2 and running:
Go to org > gnome > desktop > interface, and check the box to change accels.
Select a file to delete, go to edit, move to trash, and press the delete key. This will delete the keyboard shortcut to delete a file.
Then press a key or key combination you want to use to move a file to the trash. I will hit delete.
***Be sure to uncheck the box to change accels before you close out dconf.***