Like everyone has said, time. Your beautiful boy needs to be gently eased along. If there are other greyhound people around you, playdates are wonderful even if he doesn't want to interacr too much. You need to gently push him outside his comfort zone. By that I mean take him places but not ones that completely overwhelm him. Never force him to interact with people but if he is food motivated at all, treats from others when he feels safe can work wonders. Your job is always to give him a sense of both safety and confidence. A month is really nothing yet. But what a joy to behold when these shy guys blossom.