It sounds so simple and it is.  Here are a couple suggestions

  1. When mowing, don’t blow the grass clipping toward the compressor unit.  The clipping will stick to the fin and build up a layer
  2. Keep leaves and other debris from piling up around the base of the compressor.
  3. Keep landscape plants from touching or growing over the unit.
  4. Don’t let kids play with the unit, they seem to love throwing dirt balls at the condenser or dropping them into the compressor fan.
  5. Avoid using the water hose, you might just be turning the dirt into mud.