I noticed something Sunday at the church my family attends. Like all other areas of life, there is an unwritten communion etiquette... (non-Biblical- definitely cultural according to one's tradition)
Don't speak to anyone, other than a thank you for the elements.
No full on eye contact. If you do make eye contact, look away quickly. If you must smile at another celebrant, do so sheepishly.
Don't look to anxious when coming to the front (in a tradition which allows you to come at your leisure). You have to sit for a moment to make sure others know you are taking this moment as seriously as Paul wanted you to. But, do not take too long, lest anyone think you have serious sin issues in your life.
Take a small piece of bread. You don't want to look hungry. Plus, you don't want to choke on the tiny amount of wine/ juice you are about to receive.
Name some more.