There are two easy steps to take on a monthly basis to help your unit operate more efficiently. The first thing to check and make sure the condensing unit outside is not covered up or obstructed on the sides. The outside unit draws air into the system in order to have something to cool and circulate inside. Make sure nothing is stacked against your outside unit, and keep leaves and loose papers away.
The next step is to change the filters regularly. Dirty filters reduce the air flow which causes the unit to work harder, reducing efficiency and can cause the evaporator to ice up, or freeze over.