The best thing that you can do for your central air conditioner is to make sure you care for it correctly, don't overwork it, and have it maintained the way that it should be. Here are some of the things you should be doing for your system and when you should be doing them:
Shade the outside compressor before you run the air
Go outside and make sure the compressor is going to have shade during the hot part of the day. You may find that this isn't an issue due to its location. However, you may also find that you need to have something done, such as an awning put up or a tree planted to offer it a break from the relentless rays when it is working hard to keep the inside of your home nice and cool for you. While you are checking it out, clear out the area around it so it doesn't have weeds or anything else covering the vents in the sides.
Have it serviced by a tech before you run it for the first time
You really should have someone come out and service the unit before turning it on. If this is your first summer living in the home and you aren't even sure when the last time it was run was, then you definitely want it to be looked at. This way, you won't be running it while it has something wrong with it and risk completely ruining the motor or causing some other major issues to be caused.
Keep the unit as clean as possible
Keeping the system clean is going to be easier for some than others. If you live in a small home, don't smoke, have no pets and don't live in a very dusty region, then you are going to have a much easier time keeping the system clean. However, if you have a big house with many household members, lots of pets, smokers and you live somewhere like the desert where your house has a lot of dust come in, then you are going to have to put a lot more effort toward maintaining the system.
Go with a reusable filter so you can hose it off as much as you need. Keep all the vent and register covers dusted off well and have the ducts cleaned any time you feel like they may have a buildup of dust in them. However, if you are good about cleaning the filter then this shouldn't be something you need to worry about very often. Companies like Lakeside Heating & A/C Inc. can help.