To motivate a person to work hard he/she must have the following attitude:
1. Self Confidence - failure is not a problem, its serve's as a tool to mold us to become a better person
2. Being happy - he/she must be happy to do such work everyday
3. Vocation - sometimes, we work not because of the big salary but the courage to help others and to contribute for the better society.

With this three important things, I think  those are already enough advice to motivate others.