Reduce the Density of Allergens - Keep your doors and windows closed. While the nice weather invites most people to open the windows, this also invites the pollen indoors. Keeping the windows closed and using air conditioning minimizes the pollen and also reduces dust mites because the humidity has been reduced.
Vacuum your carpets at least once or twice a week using a vacuum with a HEPA filter to reduce the dust the vacuum cleaner puts into the air.