I have photographed many weddings, and if I was only allowed to offer one piece of advice it would be this:
Be in the moment.
Don’t worry about the reception details while you are getting ready. Don’t stress over your first dance at the ceremony. Don’t be anxious about the ceremony when you are getting your hair done.
Be present in each moment.
Embrace your wedding day, each step of the way, because it goes by way too fast.