Basically, you curse/bless/grant powers by speaking in high imperial.
The more confused the target is the more effective it is. (Basically, the more you know about high imperial, the less it affects you)
Edit: I forgot: Sticks
I just read this series as well!
Overall I really like reading it and I found the method of storytelling to be really innovative and creative. My biggest problem was I found Kvothe too perfect