I had other info, and almost forgot to post it!! For this reason, I serve it up to you list-style....
Buy your train tickets ahead if you can.
Don't forget to buy your Oyster Card (if going to London) at the bigger tube stations.
Eat Fruits and Veg
Drink Lots of Water
Book your hotel the night you return--you WILL be too tired to drive.
Go overseas in Early December--you get the Christmas without the crowd.
Another great time is in November--no crowd at Eurodisney, avoid travel on US Thanksgiving
Bring a collapsable bag for Shopping.
Bring Benedryl, ibruprofen, peptobismol, vicks baby rub (coat inside of nose with this, as you travel.)
PLEASE ADD MORE IDEAS IF YOU HAVE THEM! :) xooxxoxoxoxo