How to motivate individuals to do knowledge sharing?

To motivate individuals to share their knowledge, we need to influence them positively and this is truly an “art”. We need to master this and apply it in our daily life. The reward effect is a vital and critical element in pure knowledge management. The average organizational reward system causes people not to acknowledge knowledge management initiatives, which, is one of the reasons that a significant proportion of such initiatives fail.
Any thoughts on how to motivate for knowledge sharing?