What do you do if you arrive at your hotel and the front desk tells you they have no reservation for you?
Before you go...print all confirmation documents and file them away the very minute you book your hotel online. Then, when you're getting ready to leave, grab that file. Keep a copy with you and show it when you check in. It's always a good idea to have two copies. One in your carry-on bag and a second one given to your travel companion.
If you've booked your accommodations over the phone, ask for email confirmation as well as the name of the customer-service agent with whom you've spoken. Then, keep that info with you as well.
If you want to be even more organized, forward all necessary documents to an itinerary app.
It’s also not a bad idea before you take off on your vacation to confirm all hotel and restaurant reservations at least one week in advance.