The easiest and most sincere way to show gratitude is not just at Thanksgiving or Christmas or birthdays, but all throughout the year with a simple, “thank you,” while meeting their needs.  You can’t maintain a good relationship by just showing appreciation one or two times a year, each contact is an opportunity to strengthen the relationship with the client/customer.  You should know at any given moment how your relationship is with each client.  However, if you want to do something extra for the holidays remember to make any gift something that meets their needs or goals or wants, and not just something that you can afford.   Remember, business is made through relationships, so give a gift that builds up the relationship, that is the best benefit for your business.