I think there are some interesting points here for any first time traveller, regardless of age. I suppose the key things are:

*Some way to keep in touch. I'm in two minds about the cell phone idea. People were more resourceful before they all had cell phones and internet connections (I've never travelled without one and find myself reliant on it). OTOH, a cell phone is your best friend when it comes to dealing with a missed connection.

*Contingency. Anyone who travels a lot knows that happy travel is all about correct observation of the seven Ps. A number to call if a hotel is required, the number for the airline reservation, money for food and so on. Some advanced knowldge of a strage airport is always helpful.

Edited to say: Dare I add the the highly important bit about shutting up and doing exactly as he's told if anyone from US Immigration, customs or the feared TSA gives him any hassle (AMS won't be a problem, the immigration people there are thoroughly chilled out).