There is really not a lot a homeowner can do regarding maintenance on their own unit. You can wash the condenser coils off with a water hose. I would disconnect power to it first. If you've changed your filter regularly and used a high quality filter. Your coil is probably fine and does not need cleaning. Evaporator coils that have had the filters changed regularly and not the 59 cent cheapos at the grocery store. Will really never need a coil cleaning. Other than that. A technician needs to come out and do a once over on it.
I like DIY'ers. They pay better to fix.