What do you think is the most important factor in running an efficient manufacturing unit?

A manufacturing unit requires commitment of time, energy and resources, you need to have confidence going into it that you have what it takes to succeed in the business .
Your personality and skill-set must be geared toward effective leadership in the manufacturing environment.
And You must have the financial wherewithal to make the substantial capital commitment at the front end of the process while waiting for the payoff at the back end.
You need to be have the requisite administrative and managerial skills to coordinate the many people and processes that constitute a manufacturing enterprise. 

Proper plan or a blueprint of the entire manufacturing unit.

Properly installed plant units (manufacturing equipments required to make the intended product).

Highly trained and skilled manpower (i.e.,from the top management the low level workers)

Good quality raw materials to make the products.

Good storage facilities

Good transportation system to transport the finished products.

Good financial set up

First of all sufficient power supply & back up generators. second plant machinery & manpower.