I've been showing homes for over 9 years now, and there is one thing more than any other that starts a showing poorly: cracks in the driveway. I always point out serious cracks to my clients, but they usually see them anyway and they have their guard up wondering what other concrete problems they may face.
Whether you're selling your home or not, if you have any cracks in your driveway, porch or front step, use a concrete caulk (available in just about any home improvement store) to seal the cracks. Water is the enemy! By sealing the cracks, you will typically be able to stop water from penetrating into the crack and causing more damage.