1) Take off your shoes? Where have they been today?
2) Change the air filter in your air handler. The more dust particles removed from the air, the less that will wind up on the carpet.
3) Vacuum, Vacuum, Vacuum. Especially with homes that have occupants younger than six or older than sixty. These age groups are more affected by dog/pet dander and dust particles. Frequent vacuuming is the easiest and best way to keep your carpet clean.
4) Use a mat at your entry door. This is your first line of defense!
Carpet, tile and wood/laminat cleaning is just like exercising……Your carpet will look, last longer and you will see great results from your own efforts.!