High Sierra: Set a Global Shortcut to Lock Screen
Some time ago, I made ftiff/MenuLock to help users lock the screen of their Mac with a simple key shortcut (CMD+L, like on Windows).
In High Sierra, this will be native with CMD+CTRL+Q, and I will deprecate MenuLock.
But this doesn't mean you cannot change the shortcut. macOS has a built-in way to change shortcuts:
Open System Preferences
Open Keyboard Preference Pane
Go to Shortcuts tab
Select "App Shortcuts"
Click "+"
Select "All Applications", then type "Lock Screen" (it is case sensitive) and type your shortcut.
Quit System Preferences
Now, you can use CMD+L to lock your Mac. And it's changed in the Apple Menu!
Note: This shortcut is system-wide and will take precedence over any other shortcut, like going to location bar on Safari. Learning CMD+CTRL+Q is best ;-)