Step 1. Make sure the ground alongside the foundation is sloped away from the house. Your yard should be graded to direct water to an appropriate drainage area.
Step 2. Keep the gutters clean and free of obstructions so that water is directed away from the house's foundation (see "eHow to Clean Gutters').
Step 3. Caulk any openings around basement windows or doors.
Step 4. Paint the basement walls with waterproof paint.
Step5. Install a sump pump that has an automatic switch. (Also consider installing a generator for your sump pump in case there is a power failure during a storm.)
Step 6. Consult an established waterproofing or landscape contractor if there is a need for more serious remediation projects, such as installing underground drainage or regrading your yard.