CMD + D
I was used to use different tools like “Beyond Compare” with different editors but Phpstorm has builtin functionality.. good enough not to use separate tool. You can select two single Files and it will compare these files. If you choose two folders it will compare the structure of the folders. Also allows you to copy files or compare to matching files in the structure.
In Version Control you can compare the changes to your local version.
CMD + Alt + L
SHIFT + SHIFT
Opens a fast search console which search for files, classes and symbols. Fastest way to go to a specific file.
CMD + E
I use this all the time. It opens a window with your last used files. If I have to switch between to Files its just CMD + E followed by RETURN. This saves a lot of time.
ALT + click
Gives you the possibility to use multiple cursers. Extremely useful if you have a few lines there you want to change the exact same thing.
CMD + B or CMD + click
Jumps to the definition of the Class, Method, Function or Variable.
CMD + SHIFT + F
Detail Search with a lot of options plus a preview view of your search. I highly recommend you to check Custom Scopes help a lot for searching.
CMD + SHIFT + N
Creates a scratch file there you can make notes or just try some code snippets. The files are not stored in your projects and will be displayed even if you switch project.
CTRL + T
Opens the Refactoring dropdown.
I think PHPStorm is a really great tool. But its so complex that I regularly discover new features I wish I would have known before.