Hi Mili,
Cost reduction does not fully mean that you concentrate on the items like switching off the lights, AC etc but to enhance the productivity to maximize the profits
You may reduce Cost by "Increasing efficiency to maximize profits" and i feel that Lean Methodology is the best tool that is available to support to any organization (Mfg, Service, etc)
For your reference:
When do I use Lean?
The ideal time to begin utilizing Lean principles is after your key business processes have been defined and before a Six Sigma project pool has been developed. Value Stream Mapping identifies which method of improvement will achieve the greatest results, immediately. Some business processes need to be leaned before applying Six Sigma to eliminate variation. Others require a complete re-design or a development of a new process using Design for Six Sigma (DFSS).
Find attached the Diagram - Lean Valuestream