Indoors, get rid of their webs. Cleaning is the best method of spider prevention, so go through your home vigorously sweeping, dusting, and vacuuming. Do this weekly for a couple of months to destroy existing nests, not giving spiders time to rebuild and lay eggs.
Outdoors, get out the hose. Use the water to knock webs and spiders out from under the eaves. Repeat weekly or as necessary. Keep grass and weeds that grow near the house cut low, and likewise keep shrubs near the house small and neatly maintained.