7 mistakes to avoid on your first international trip

The experience of international travel is unforgettable: Leaving home, breathing in unfamiliar smells and gazing at new sights for the first time in a country you've never visited. But the mistakes you make on those first trips can also be memorable. Take it from me as someone who has visited 36 countries and spent the last year traveling with my husband and our 1-year-old on a budget. We have made plenty of mistakes along the way.

Here's how you can avoid seven common mistakes with a little planning.

Not applying for your passport in time 

Leaving the country for the first time isn't something you can necessarily do on a whim -- unless you already have your U.S. passport.

Otherwise, it takes from six to eight weeks, unless you pay extra to get the process expedited. Renewal or first-time application fees for an adult U.S. passport with a standard six- to eight-week processing time costs $110, according to the State Department. It will cost an extra $60 to expedite the application to a two- to three-week processing time and an extra $16 for a one- to two-day delivery option. For the truly last-minute need, FedEx and RushMyPassport offer even faster expedited passport services that can add an extra $449 on top of standard passport application or renewal fees.

Here are other tips to check out in the TPG guide to 6 passport mistakes that could leave you stranded at the border.

Not applying for your visa in advance 

Although international visa requirements and fees vary by country, there's often a surcharge for applicants needing theirs in a rush. China charges an extra $25 to $37 per person for expedited applications.

Not avoiding costly currency exchange mistakes

Airport currency-exchange kiosks provide the convenience of changing your money at the last minute before you take off or after you land. But it will cost you. Exchanging $500 in U.S. dollars for euros at a Travelex location at the airport could amount to 20 fewer euros than if you exchange the same amount at a Wells Fargo or Bank of America.

Request currency from your local bank before your trip because banks and credit unions offer some of the best exchange rates, and may offer perks to select members. As a member of Bank of America's Preferred Rewards program, I get a 2% discount on foreign currency exchange rates. The catch is that I have do this in advance — something I have never managed to do. Bank of America suggests customers request currency three business days in advance.

With some countries, calculating exchange rates involves some challenging multiplication or division. To make things easier on myself, I refer to a handy exchange-rate calculator app on my phone to track what I'm spending as I go and not inadvertently spend $20 on medicine for my child that should otherwise cost about $6-10. (This happened once before downloading a currency converter app.)

Using a currency other than the local one 

While traveling in South America for six months, I took a side trip to Uruguay from neighboring Argentina. Because it was only a one-week trip, I didn't want to withdraw too many Uruguayan pesos and then later have to change the currency back, which would have added exchange costs. Short on the local currency, I made some purchases with U.S. dollars and Argentine pesos when credit cards were not accepted. This came at its own cost because local shops and restaurants gave me change in the local currency, not necessarily matching the exchange rate I would have received at a bank.

Not avoiding ATM withdrawal fees

Even with the best advance planning, there may be times while you're traveling abroad when you need to get extra cash. If that's the case, do your research about ATM fees and find out whether your bank partners with local institutions so you can save on foreign ATM withdrawal fees (as Bank of America does), has international locations outside the U.S. (like Citi does), waives fees altogether (as is the case with the Capital One 360 Checking account), or will reimburse you for ATM fees (as is the case with the Schwab Investor Checking account ATM card).

Using a credit card with foreign-transaction fees

You may not realize it when you're using your credit card at home, but cards many charge a foreign transaction fee of about 3% — essentially canceling out any rewards points you might earn — each time you use your card during your international travels. That was a rude awakening for me when I was old enough to have and use my own credit card on my travels.

Bookmark this definitive guide to the best credit cards with no foreign-transaction fees to find a suitable card to cut costs on your next international trip.

Not doing duty-free the right way

It pays to do your research before buying. Figure out what a fair price for an item should be and compare prices on duty-free products at stores in different terminals at your airport. TPG explored 50 airports comparing 13 popular duty-free items across locations and found huge variations in prices between and within airports. Pro tip: Overall, the best duty-free deals are in Kuala Lumpur, Singapore and Grand Cayman.