XCode shortcuts

Command + 0 
Show/hide navigator panel, especially when you open a file in a new window, there is no navigator panel in the new window by default.

Command + Shift + F
Quick way to Search tab in navigator panel

Command + Shift + O
Quick way to search and open a file

Command + Shift + K
Clean the project

Command + Shift + Number 0
Open Apple documents

Option + Left click
Check description of the class, method, variable

Control + 6 
Search in the files and quick jump to properties/methods

Command + R
Run the project

Command + B
Build the project

Command + U
Run all the tests

Command + Control + Option + U
Run the opened test

Command + Option + Shift + Left/Right
Collapse/Expand functions

Command + Option + Left/Right
Collapse/Expand the current enclosing scope

Control + A
Go to the beginning of the line

Control + D
Delete the selected section or the following characters

Control + Shift + Left/Right
Select backward/forward