In 2004, the travel tips thread sparked some interesting ideas for us to consider. Might it be a good idea to start a thread specific to dining? If not, just let this thread pass into the abyss of threads unanswered. Here are my two:

Turn on the hot water before you use the restroom so it will be warm when you need to wash your hands.

When dining at a Mexican restaurant, throw trash and plates into empty chip baskets for your server to pick up so your table stays nice and clear.