Remove Shoes. While it may take time to "train" everyone in your home to do it, removing shoes before entering a carpeted room will dramatically reduce wear and tear and help keep dirt at a minimum.  

Vacuum. Seems like a no-brainer but REGULAR vacuuming (1 or 2 times a week depending on your foot traffic) is crucial to keeping your carpet clean and allergen free. Run the vacuum twice across the carpet in different directions (crisscross pattern) to do a thorough job. Hint: If your vacuum has a bag, be sure it is not overfull for the best results. Always start with a clean vacuum whether bagged or bagless.

Test for Color Fastness BEFORE Applying Any Cleaning Solutions. Whatever cleaning solution you use, always test it first. Wet a cloth with the solution and test behind a door or somewhere inconspicuous. If the carpet changes color or bleeds on your blotting rag, choose a different solution. 

Deodorizing. If you have pets, deodorizing is especially important. You can make your own carpet deodorizer with baking soda and a few drops of essential oil. Also, using a small amount of baking soda in your vacuum bag helps keep odors down.  

Steam Clean every 6-18 months. Depending on the foot traffic, you should give your carpets a good steam cleaning to remove ground in dirt and allergens every 6-18 months. You can rent a steam cleaner from K&B True Value or purchase one depending on how often you need to steam clean.