Gamification Mechanic : Experience Points
Experience points are what should be the corner stone of all your gamification endeavours and primarily aimed at driven the behaviour you would like to encourage more of.
For example if you would like to have your staff sell more of a specific item or perform a specific action to a higher level of accuracy, the experience points should be rewarded when someone indeed carries our what you would like them to do.
In a game we usually are able to level up thanks to completing all the experiences necessary for the first level. In business you may not have many levels, so rewarding the desired behaviour may need to be thought through a bit more and creatively.
Where should you apply experience points, well in my view in all your gamification projects especially when you aim to encourage behavioural change. What you need to have in mind is the journey you want your player to follow and the behaviour you would like to reward along the way.