1) Set a Comfortable Temperature at 24Deg C- & use sleep mode in the night to get the comfortable cooling as per body, we need less cooling in the night( In manual system Don't set the temperature at the coolest because the compressor will never turn off and this will cost you money. To get the comfortable temp.turn the AC on with coldest setting on thermostat , when you feel comfort temp cut of the AC compressor through thermostat, it will reduce the power consumption.
2) Have Refrigerant Levels Tested - ( Complusory servicing to be done before summer starts & one before rainy season & last service at the end of season to save corrosion in side the units body) through company service center. They can test your system to determine if you have a refrigerant leak., motors noise, viberation in indoor unit of split AC & anti Viberation pads of Compressor. If required always use genuine spare parts to lower breakdownd & power bill. Install a good quality Voltage stabilizer to get the necessary Voltage & reduce your electricity bill. Dont Install under capacity machine it will save your initial cost , but increase your electricity bill in summer.
3) Seal Off Any Droughts - Droughts and gusts of wind can really cool down your home when your trying to warm it up in winter. Drought stoppers and sealing cracks can reduce these droughts which will keep the warmth in and reduce your heating bills substantially.
4) Learn How To Use Your System - If you are not entirely sure how to use your air conditioning system, you are probably using it wrong. Speak with an air conditioning contractor for some good advice on how to run your air conditioner.
5) Clean Filters & Ducts -Finally, give your ducts and filters a quick clean. It is the simplest thing to do to get your hvac system to run better again. ( People in India are not very well educated towards their health, duct cleaning is still a neglected part in HVAC industry. Only few MNC's are intrested in duct cleaning. We cannot reduce electricity cost with duct cleaning, but it will help to reduce lot of Air borne deceases, yes filter cleaning will help to cut the power tarrif and increase the AC units life.)