Wear comfortable shoes. Airports are big. You can bring your own water, just be careful when you open it once the plane is in the air. The pressure change can make the water squirt.
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If you can, wear shoes that can be removed easily. They'll probably ask you to remove your belt, if you're wearing one, at security. Also bring plenty of things to entertain you or the flight can be quite boring. Cash is also good to have. Depending which airline you're using, the meals might have to be paid for. If so, they only take cash. However, try to avoid buying their meals. It's better to buy your own and bring it on the plane, if a free meal is not provided.
For 6 days, you won't need a suitecase very big, but then again, I travel very light and most people I know bring lots of crap with them. It's a personal preference. It's always good to carry an outfit in your carry-on in case your luggage was lost. Also, make sure whatever you pack is packed neatly and tightly or it's going to be a mess once you get it back. Security will most likely open up and rummage through your stuff.
Don't be afraid to see the truth, even if no one wants you to. Be yourself and not a fool. Don't ever be afraid to speak your mind and listen to criticism. Dissent is keeps our country progressive and willingness to challenge yourself is what keeps yourself ever evolving.