The 3 key principles he calls out as being true motivators are:
Autonomy: People want to have control over their work.
Mastery: People want to get better at what they do.
Purpose: People want to be part of something that is bigger than they are.
If you don’t have the time, I suggest that you at least watch this phenomenal video from RSAnimate that distills the principles quite succinctly (with voice over from Daniel himself).