You can make your air conditioner work better by reducing the size of the job it has to do. You can do this by improving the building or reducing the internally generated loads that your air conditioner must deal with.
Improving the building “envelope” includes things such as increasing insulation levels or shading windows or reducing air leakage. Such improvements will reduce energy spent on heating and cooling, but may require substantial time or investment. When putting in a new roof or new windows, it is usually cost effective to use high-efficiency products. “Cool” roofing, for example, can save half a ton of cooling and a lot of energy over the year.
Reducing internal loads can be simpler. Shut off unneeded electrical appliances, lights and equipment. Shift appliance use (such as washers and dryers) to cooler times of the day. Use local exhaust fans to remove heat and humidity from kitchens and baths. Buying Energy Star or similarly efficiency appliances helps as well!