⌘ Command + Double-Click on a symbol
: Jump to Definition of a symbol.
⌥ Option + Double-Click on a symbol
: Find Text in Documentation of a symbol. (Only works if you have they symbol's Doc Set installed.)
Favorites Bar:
Favorites bar is just like you have in Safari for storing - well - favorites. I often use it as a place to store shortcuts (which you can do by drag-dropingdropping) to files I am using right now. Generally this is more useful when I'm working with a large or unfamiliar project.
To show the Favorites Bar, select the following menu option:
View
>Layout
>Show Favorites Bar