I worked a local sprint triathlon for a friend a couple of years ago at Lake Caroline. I have a kayak that I used to help "save" people during the swim.
This is what I observed....panic.

The swim is confusing if you are not used to swimming with a lot of people around you from what I am told. Plus, you are all jacked up and have a tendency to shoot your wad before you need to.
So, with that being said, swim a lot and don't get too excited once the race starts....relax.