I take printouts of all my hotel reservation confirmations, and keep them until I pay the bill on checkout.

Also a printout of every phone number I might want to use, both personal and travel-related, both at home and in the foreign country. (They may be in your cell phone but what if you lose it ...)

If I have travel insurance I take along the relevant documents.

I put on line (accessible only to me) the web sites of any financial or other companies I might want to access on the internet while traveling.

Related suggestion: call all your credit card companies and tell them where you'll be traveling, especially if it's a foreign country.