Anytime you are outside of a text input field in Karbon, press Alt (Windows) or Option (Mac) ahead of the following letters to perform the corresponding action:
Alt + C for a new Contact
Alt + E for a new Email
Alt + N for a new Note
Alt + W for a new Work item
Alt + S to open Global Search
Cntrl + Alt + T for a new Time Entry
Alt + T to start the Timer
After composing an email:
⌘ + Enter (Mac) / Ctrl + Enter (Windows) to send