• Clean regularly: Unplug and remove all food and bottles and food packets. Clean and wash the shelves with warm water and detergent and the interiors of the fridge with warm water and baking soad.
• Keep non veg items in small separate packets and on a plate, preferably so that the floor of the freezer remains clean and unstained.
• Remove old food, half empty bottles from the fridge.
• Keep fridge away from heat sources. It will be good to remove it from the kitchen. Good, but maybe not feasible.
• Clean the coils at the bottom or back of the fridge regularly.
• Peel  off the door gaskets if possible, clean them and fix them back, making sure that it is not letting air into the refrigerator.
• Close it well. Make sure that the door of the fridge is closed when you walk away from the fridge.
• Keep it away from the walls to let a good air flow around it.

Source: energymanagertraining.com