3. Mismanaging your money
Whether it’s by using traveler’s checks (obsolete), getting cash before you go, or by using exchange bureaus at airports, or by bartering vestigial organs, you don’t look for the best rates.
What you should do: Use the ATM for cash and a credit card for all your purchases. Check if your bank has a partner ATM network in the country you're visiting and it may cost you nothing to take out local cash. Anything else can go on credit cards -- just tell your issuer you’re leaving so they don’t flag your card for fraud after they see 15 piñatas show up on your recent purchases.
4. Booking too early
People get excited about their trip and, to make it real, book their flight right away. Or they forget and wait until the last minute. Both are a mistake.