More and better signage is a simple (and often cost-effective) way to improve accessibility for a range of people.  A well-thought out sign system can help everyone become more aware of their surroundings.  The JMU Access Partnership produces the Sign Design Guide which can be purchased for £20.  Bristol City Council also provides guidelines for improving signage.

You may want to consider using Makaton signs to communicate with learning disabled customers, or more visual information for deaf people.