Whatever form of cleansing you do, from Christian house blessing to pagan drumming circle -- and there are many good ideas above -- you would do well to follow it up by "sealing" all door and windowsills with a mixture of salt and water (sprinkle it everywhere), to keep whatever's been shooed out from returning. If you've used burning sage or a similar incense as well, you'll have incorporated all four elements (earth and water in the salt water, air and fire in the smoke) into your ritual, which is good.
Then, plant a rosemary plant by each door for an extra layer of protection...that'd be the strongly scented herb Crow Sister refers to above.