Bob Lee has put together a list of of many great Xcode shortcuts to help you get the most out of your time in the Xcode 8 environment.
Each shortcut complete with gif animations so you can see exactly what they do.
You can find the guide in 3 parts in the iOS Geek Community: Part 1, Part 2, Part 3.
A handy series of guides for those looking to increase their efficiency in Xcode.