1. Keep a copy of your passport (or upload a photo to the cloud) in case you need an emergency replacement.
2. Check your debit and credit cards to see which have the best terms for international transactions and exchange rates. Some cards will ding you for every international transaction, or use one exchange rate for the year regardless of whether todays rates are better. This can get very expensive!
3. Save locations, cities, and navigation to your phone via googlemaps for offline access without using data or wifi. When you are used to unlimited connectivity, this one is clutch for keeping your phone on airplane mode/wifi only the whole time. (Beware the temptation to turn on calla or data "check in quickly" which may result in your phone processing an automatic data dump costing you hundreds.)
Happy travels! M&C