Depending on the fabric the shoe is made from, there are three things I like to try. First, try a pencil eraser. Erasers are not abrasive and they usually work well on leather and patent leather. A blend of toothpaste and water is a good option for tougher scuffs and soles. A rubber band is also slightly effective for mild scuffs when an eraser is not available. These are just some methods I like!
If you're interested, you can prevent scuff marks from happening entirely. Check out SKUFF Protective Coatings. It's a clear protective finish for shoes that shines, waterproofs, and protects from scuffs and stains - essentially keeping shoes clean and looking new for years longer. Just a good tip for people who care! :) http://www.skuff.us