Dear Prathiyankara,
Others have given some suggestions and also advertising their services. So, let me ask a few questions and make comments.
Do you subscribe to your management's thought that you can motivate people to improve their productivity without incurring cost?
How large is your organization and how long has it been in existence? What is the background of the owners and what qualifications do the workers hold? More the information you give about the scenario, more precise will the help that you will get here from experts like Dinesh Divekar. He has asked you some very pertinent questions. If you have no answers to those questions, obtaining answers will cost both time and money.
What is your background and what do you know about what motivates people? There are only two basic approaches: "the carrot and the stick" based on circumstances. Please read and digest the info at
Improving Employee Morale and Motivation | BizFilings Toolkit