Here’s a rundown of what should go in your suitcase:
Shirts/blouses. Bring up to five short-sleeved or long-sleeved shirts or blouses (how many of each depends on the season) in a cotton/polyester blend. Shirts with long sleeves that roll up easily can double as short-sleeved. Look for a wrinkle-camouflaging pattern or blended fabrics that show a minimum of wrinkles. Synthetic-blend fabrics (such as Coolmax or microfiber) often dry overnight.
Pants/shorts. Bring two pairs: one lightweight cotton and another super-lightweight pair for hot and muggy big cities. Jeans can be too hot for summer travel (and are slow to dry). Many travelers like lightweight convertible pants/shorts with zip-off legs. While not especially stylish, they’re functional in Italy, where you can use them to cover up inside churches while still beating the heat outside. Button-down wallet pockets are safest (though still not nearly as thief-proof as a money belt). If you bring shorts, one pair is probably enough. Shorts can double as a swimsuit for men when swimming in lakes or the sea.
Underwear and socks. Bring five sets (lighter dries quicker). Bamboo or cotton/nylon-blend socks dry faster than 100 percent cotton, which lose their softness when air-dried.
Shoes. Bring one pair of comfortable walking shoes with good traction.Mephisto, Ecco, and Rieker look dressier and more European than sneakers, but are still comfortable. Sturdy, low-profile tennis shoes with a good tread are fine, too. For a second pair, consider sandals in summer. Flip-flops are handy if you’ll be using bathrooms down the hall. Whichever shoes you bring, make sure they are well broken in before you leave home.
Sweater or lightweight fleece. Warm and dark is best — for layering and dressing up.
Jacket. Bring a light and water-resistant windbreaker with a hood. Neutral colors used to look more European than bright ones, but now everything from azure blue to pumpkin orange has made its way into European wardrobes. A hooded jacket of Gore-Tex or other waterproof material is good if you expect rain. (For summer travel, I wing it without rain gear — but always pack for rain in Britain and Ireland.)
Tie or scarf. For instant respectability, bring anything lightweight that can break the monotony and make you look snazzy.
Swimsuit. To use public pools, you’ll need a swimsuit (men can’t just wear shorts; and in France, men need to wear Speedo-type swimsuits — not swim trunks).
Sleepwear/loungewear. Comfy streetwear — such as shorts, leggings, T-shirts, tank tops, yoga pants, and other lightweight athletic gear — can be used as pajamas, post-dinner loungewear, and a modest cover-up to get you to the bathroom down the hall.
Documents, Money, and Travel Info
Money belt (or neck wallet). This flat, hidden, zippered pouch — worn around your waist (or like a necklace) and tucked under your clothes — is essential for the peace of mind it brings. You could lose everything except your money belt, and the trip could still go on. Get a lightweight one with a low-profile color (I like beige). For more, see my article on money belts.
Money. Bring your preferred mix of a debit card, a credit card, and an emergency stash of hard US cash (in $20 bills).
Documents. Bring your passport; plane, train, and rental car documents or vouchers; driver’s license; and any other useful cards (student ID, hostel membership card, and so on). Photocopies and a couple of passport-type photos can help you get replacements more quickly if the originals are lost or stolen. In your luggage, pack a record of all reservations (print out your hotel confirmation emails). Bring any necessary contact info if you have health or travel insurance.
Guidebooks and maps. Pack the travel info you’ll need on the ground (or download it into your ereader). I like to rip out appropriate chapters from guidebooks and staple them together, or use special slide-on laminated book covers.
Small notepad and pen. A tiny notepad in your back pocket or day pack is a great organizer, reminder, and communication aid.
Journal. An empty book to be filled with the experiences of your trip will be your most treasured souvenir. Attach a photocopied calendar page of your itinerary. Use a hardbound type designed to last a lifetime, rather than a floppy spiral notebook. My custom-designed Rick Steves Travel Journals are rugged, simple blank books that come in two sizes. Another great brand, with a cult following among travel writers, is Moleskine.
Small day pack. A lightweight pack is great for carrying your sweater, camera, guidebook, and picnic goodies while you leave your large bag at the hotel or train station. Don’t use a fanny pack — they’re magnets for pickpockets.
Toiletries and Personal Items
Toiletries kit. Because sinks in many hotels come with meager countertop space, I prefer a kit that can hang on a hook or a towel bar. Before cramming it with every cosmetic item you think you might use, ask yourself what toiletries you can live without for a short time. (But women may want to estimate how many tampons and pads they might need and pack them along — even though most familiar brands are sold throughout Europe, packing them is easier than having to buy a too-small or too-large box in Europe.) For your overseas flight, put all squeeze bottles in sealable plastic baggies, since pressure changes can cause even good bottles to leak. Pack your own bar of soap or small bottle of shampoo if you want to avoid using hotel bathroom "itsy-bitsies" and minimize waste and garbage.
Medicine and vitamins. Even if you check your suitcase on the flight, always carry on essential toiletries, including any prescription medications (don’t let the time difference trick you into forgetting a dose). Keep medicine in original containers, if possible, with legible prescriptions.
Glasses/contacts/sunglasses. Contact-lens solutions are widely available in Europe. Carry your lens prescription, as well as extra glasses, in a solid protective case. If it’s a sunny season, pack along sunglasses, especially if they’re prescription.
Sealable plastic baggies. Bring a variety of sizes. In addition to holding your carry-on liquids, they’re ideal for packing leftover picnic food, containing wetness, and bagging potential leaks before they happen. The two-gallon jumbo size can be used to pack (and compress) clothing or do laundry. Bring extras for the flight home.
Clothesline. Hang it up in your hotel room to dry your clothes. The twisted-rubber type needs no clothespins.
Small towel/washcloth. You’ll find bath towels at all fancy and moderately priced hotels, and most cheap ones. Some people bring a thin hand towel for the occasional need. Washcloths are rare in Europe, so you might want to pack a quick-drying microfiber one. Disposable washcloths that pack dry but lather up when wet (such as Olay’s 4-in-1 Daily Facial Cloths) are another option; cut them in half to make them last longer.
Sewing kit. Clothes age rapidly while traveling. Add a few safety pins and extra buttons.
Small packet of tissues. Stick one of these in your day pack, in case you wind up at a bathroom with no toilet paper.
Travel alarm/wristwatch. Make sure you have an alarm to wake yourself up (your smartphone, a little clock, etc.). At budget hotels, wake-up calls are particularly unreliable.
Earplugs. If night noises bother you, you’ll love a good set of expandable foam plugs. They’re handy for snoozing on trains and flights, too.
Hairdryer. These are generally provided in $100-plus hotel rooms. If you can’t risk a bad-hair day, buy a cheap, compact hairdryer in Europe or bring a travel-friendly one from home.
Note that many of these things are high-ticket items; guard them carefully or consider insuring them.
Smartphone/mobile phone. Bring your smartphone to keep in touch with folks back home and for accessing resources on the road such as email, travel apps, and GPS. If you just want to make calls or send texts, a simple US mobile phone might work perfectly in Europe — or you can buy a cheap mobile phone to use while you’re there.
Digital camera. Take along an extra memory card and battery, and don’t forget the charger and a cable for downloading images.
Tablet, ereader, or portable media player. Download apps, ebooks, and music before you leave home.
Laptop. If you’ve got a lot of work to do, or want to keep your photoblog updated, a laptop can be worth the weight.
USB flash drive. If you’re traveling with a laptop, a flash drive can be handy for backing up files and photos. As an alternative, consider free cloud storage sites — such as Amazon Cloud Drive, Apple iCloud, or Dropbox — that you can access anywhere.
GPS device. If you’ll be doing a lot of driving and have a portable GPS device at home, you could buy European map data to use on vacation.
Headphones/earbuds. These are a must for listening to music, tuning in to audio tours, or simply drowning out whiny kids on the plane. (I never travel without my noise-canceling Bose headphones.) Bring a Y-jack so you and a partner can plug in headphones at the same time.
Chargers and batteries. Bring each device’s charger, or look into getting a charger capable of charging multiple devices at once.
I don’t advocate bringing everything listed here. Choose the items that fit with your travel style and needs.
Picnic supplies. Bring a plastic plate (handy for dinner in your hotel room), cup, spoon, fork, and maybe salt and pepper. The Fozzils picnic setfolds completely flat. Buy a Swiss Army–type knife with a corkscrew and can opener in Europe (or bring one from home if you’re checking your luggage on the plane).
Water bottle. The plastic half-liter mineral water bottles sold throughout Europe are reusable and work great. If you bring one from home, make sure it’s empty before you go through airport security (fill it at a drinking fountain once you’re through).
Fold-up tote bag. Look for a large-capacity tote bag that rolls up into a pocket-size pouch. Use it for laundry, picnics, and those extra souvenirs you want to take back home.
Small flashlight. Handy for reading under the sheets after "lights out" in the hostel, late-night trips down the hall, exploring castle dungeons, and hypnotizing street thieves. Tiny-but-powerful LED flashlights — about the size of your little finger — are extremely bright, compact, and lightweight. Camping-type headlamps also do the trick.
Inflatable pillow (or neck rest). These are great for snoozing in planes, trains, and automobiles. Some travelers also swear by an eye mask for blocking out early-rising or late-setting sun.
Duct tape. A small roll of duct tape can work miracles as a temporary fix — mending a punctured bag, solving an emergency shoe problem, and so on. Conserve space by spooling only as much as you might need (less than a foot) around a short pencil or dowel.
Insect repellent. Bring some along if you’re prone to bites and are going somewhere especially bug-ridden.
Tiny lock. Use it to lock your backpack zippers shut. Note that if you check your bag on a flight, the lock may be broken to allow the bag to be inspected. Improve the odds of your lock’s survival by buying one approved by the Transportation Security Administration — security agents can open the lock with a special master key. Or buy plastic locks or zip-ties to secure zippers — be sure to pack fingernail clippers or TSA-approved scissors so you can open them when you arrive.
Universal drain-stopper. Some hotel sinks and tubs have no stoppers. This flat, flexible plastic disc — which works with any size drain — allows you to wash your clothes or take a bath.
Office supplies. Bring paper, pens, envelopes (for letter writers), and some sticky notes (such as Post-Its) to keep your place in your guidebook.
Address list. If you’ll want to mail postcards, you could print your mailing list onto a sheet of adhesive address labels before you leave. You’ll know exactly who you’ve written to, and the labels will be perfectly legible.
Postcards/photos from home. A collection of show-and-tell pictures (either digital or paper) is always a great conversation piece with Europeans you meet.
A good book. There’s plenty of empty time on a trip to either be bored or enjoy some good reading. Popular English-language paperbacks are often available in European airports and major train stations (usually costing more than their North American price). An ereader carries lots of books without the additional weight (and you can easily buy more as you go).
Gifts. If you’ll be the guest of local hosts, show your appreciation with small, unique souvenirs from your hometown.
Hostel sheet. These days, sheets are usually included in the price of a hostel, and if they aren’t, you can rent one for about $5 per stay. Still, you might want to bring along a sheet (silk is lighter and smaller, cotton is cheaper), which can double as a beach/picnic blanket and cover you up on overnight train rides.