If you are not that satisfied by the default syntax highlighting in Xcode and the pre installed themes aren’t that useful for you there is an easy way to install some new ones. At first, open Finder and navigate to:
~/Library/Developer/Xcode
(to do so press cmd+shift+g and type in the folder). now create a new folder called
FontAndColorThemes
You are now ready to color up Xcode with new themes. To find some a good starting point to search on github.com for “Xcode themes”. Typically you will find a file with the ending:
.dvtcolortheme
Copy this file to the newly created directory. If you restart Xcode now you will see your installed themes under Preferences-Fonts & Colors. If everything went fine it should look like this: