As a pilot,
here are a couple of suggestions.
Once you get through security, put your shoes back on
buy a bottle of water and just carry it in your "carry on"
go to the bathroom just prior to boarding the aircraft, especially if your nervous
If you get hungry pack some snacks, airlines are getting much tighter on what they have to offer so if you have a faorite food bring it.
Good luck and relax, enjoy the ride I would
Doc