We had only been in Tokyo four hours, and I already feared we were headed to jail.

"It's one of the most technologically advanced countries in the world, but they don't take credit cards?!" I irately asked my friend, as we stared at a rather hefty bill at a whiskey bar deep in the city's Shinagawa ward.

We had no yen on us yet. Our ATM cards did not work. And, of course, we did not speak Japanese well enough to reassure the stern-looking woman behind the bar that we would not run out on our tab.

This was the first of many instances on our trip to Japan last summer where I felt like your average underprepared, overconfident American.

I'm an experienced international traveler, mind you, and usually a good planner. But between a busy schedule at home, a reliance on a third friend who had Japan on his bucket list — but apparently did not consult any other lists — plus maybe a little cockiness, the country repeatedly threw me off my game.

Here's what I learned from my first Japanese trek. I believe I'm not being overconfident when I say it won't be my last trip there.

1. Cash is king.

Probably half the restaurants and bars we went to did not accept credit cards or virtual pay. It's not for lack of technology; they're smartly avoiding fees. Also, Japanese people don't have to worry about getting robbed at gunpoint like Americans do.

So go ahead and bring dollars to convert to yen. Plan ahead for wiring money if need be. And/or consult your bank to make sure your ATM card will work there. Mine never did.

(Side note: We made it out of the Tokyo whiskey bar thanks to a German regular there who spoke English well enough to convince our server to take U.S. dollars with a healthy tip. Talk about united nations.)

2. Shop for flights from other cities.

Delta Air Lines flies nonstop from Minneapolis-St. Paul to Tokyo Haneda Airport every day, but I saved about $500 last year by booking a $300 Delta flight to Los Angeles and then a $850 Singapore Airlines flight to Tokyo from LAX. Booking separately via Seattle was cheaper, too. At press time, though, Delta's nonstop fares from MSP for April and May were comparable, so you never know.

3. Google Translate is a godsend.

I had never used the app before Tokyo, and I would not go back without it. We held our phones up to just about every restaurant menu to translate the Japanese letters into English via this app. Sometimes the results were a bit askew, i.e. "fat pig balls" at one restaurant. But it's always ballpark-close anyway.

(Side note: The "balls" were delicious; really just chunks of pork belly.)

4. Real sushi is not like the American version.

If your idea of sushi is California rolls and other sticky-rice concoctions with fancy adornments, then maybe you should go to California instead. What we had throughout our trip was more like sashimi — raw slabs of fish served with a little rice on the side. The wider array of raw seafood offered had me turning green, but didn't stop my friends, who ordered selections including slimy sea urchin in Tokyo's famed Tsukiji fish market.

(Side note: They both regretted the sea urchin.)

5. Don't be fooled by sake.

It comes in flowery bottles you pour into little sipping cups, often in fruity or sweet flavors. Don't let the cuteness fool you into over-imbibing. Be careful. Be inquisitive, too. The servers will be happy to coach you to find your favorites.

Luckily, we learned all this before hitting the self-serve Sake Café Lab 250 in the scenic, shrine-adorned city of Nikko, where the bottles are attached to machines that operate via tokens to help yourselves. "God help us," was my friend's response.

6. Check the weather before heading to Mount Fuji.

We spent one full day and night on the iconic volcanic cone, but we barely got a glimpse of it. It was rainy and overcast the whole time. Two days later, though, while riding a train from Kyoto back to Tokyo, we got a crystal-clear view of the mountain from about 30 miles away. We were as awed as we were frustrated. If only we had switched days.

7. Spend more time in Kyoto.

Sure, I'd heard it was a nice city with a lot of culture. But I didn't fully fathom how downright soulful and soothing Kyoto would be until our two days there. We crammed in all the top sights, including the otherworldly Arashiyama Bamboo Grove, ornate Kinkaku-ji temple, Nijō Castle and the steep climb under the arches at Fushimi Inari Shrine and Mount Inari — a way better hike than our cloudy trek on Fuji.

Even better were the smaller finds, like the lesser-known temples tucked into neighborhoods and the dive-y counter eatery Chao Chao Sanjo Kiyamachi, where I had the best gyoza of my life. I would have been happy spending twice as much time in Kyoto just to stroll the clean and scenic streets and finding those more random highlights.

8. You can't conquer Tokyo in one trip.

We covered a lot of territory in our four days there, bouncing from the must-see Tokyo Tower to the eye-candy-ish Mori Art Museum to a divine tonkatsu restaurant called Butagumi up in the Nishiazabu neighborhood. We did too much bouncing around, though, with too many rides on the crowded metro trains. Find more condensed, walkable routes, and save farther-off sites for your next time there.

Also, instead of picking hotels near our chosen daytime highlights, I would've gone with one in the neighboring Shibuya or Shinjuku wards, where we spent most nights — two of them meandering through the (in)famous, narrow bar district known as Piss Alley, another trip highlight.

Fortunately, by then we knew how to pay for our whiskey.