Mold lurks mainly in showers, bathtubs and basements--anywhere it's damp and dark--so wiping down the tub or shower with your towel after bathing is a must, in order to keep bathroom mold growth at bay. Use a dehumidifier in the basement and install an exhaust fan in the bathroom.
Sorry to say it, but pollen does find its way indoors on shoes and clothing--even pets. Change into fresh clothes after spending time outside, wipe off the dog before letting him in and close the windows to keep pollen outside where it belongs. Wipe down all window sills, window frames and along the tops of doors with a damp cloth every week. An air purifier with a HEPA filter can also significantly cut down on indoor pollen.
Cleaning tips from the American Academy of Allergy Asthma & Immunology:
Use a solution of chlorine bleach (3/4 cup chlorine bleach to 1 gallon of water) to clean mold and condensation off window frames and sills, and to combat mildew on concrete floors and walls. Allow the solution to sit for five minutes, then rinse and dry. Always wear rubber gloves when using bleach or vinegar solution.
For mold or mildew in carpet, clean the back of the carpet with one part hydrogen peroxide to five parts water. If possible, remove the carpet and place it outside in the sun to dry. If not, prop the section up and use a fan to dry the area.
For mold or mildew on basement walls, try straight vinegar sprayed on the walls. Don't rinse, just air dry. A second option is combining two cups of vinegar, two cups of very hot water, half-cup of salt and two cups of Borax. Apply the solution to the affected area and allow it to sit for 30 minutes. Apply a second time, scrubbing with a soft-bristled brush, and rinse well with plain water. Don't forget to use a dehumidifier or fans to circulate the air and open the windows if possible.