Miami: South Beach

I always take a digital picture of the gas gauge to prove that I returned the rental car with a full tank. Some agencies try to charge for a minimal amount of gas when they "top off" the tank (which you're not supposed to do anyway). I've used these digital photographs to get refunds for gas charges that appeared on my credit-card bill after the fact.

If you're a woman traveling alone, or your accommodations don't inspire confidence, simply wedge a small rubber doorstop at the base of the door when you're inside the room. It'll be virtually impossible to open the door from the outside.

Flight attendants often work vampire hours and have to sleep during the day. How do we keep the sunlight from leaking into our hotel rooms? We clip a skirt hanger (or two) to the middle of the drapes to seal them together.

If you're planning to use an ATM abroad, make sure the money you need is in your checking account, because some foreign ATMs don't allow access to savings accounts. And remember to carry your bank's local phone number with you; 800 numbers generally don't work overseas.

Our bags have been stolen twice from inside locked rental cars. Now we travel with a bicycle cable and lock. If we absolutely have to leave our suitcases in the car, I hook them together by the handles and attach the whole thing to the frame of a seat or a secure item in the trunk. Even if thieves manage to get into our car, the cable will make it very difficult for them to make off with the luggage.

If your tablecloth is wet at dinner, you should prepare for rough seas. Restaurant staffers have been known to slightly dampen the tablecloth to keep plates and glasses from sliding.

By starting a blog for each trip--at blogger.com, among others--you can keep your friends and family up-to-date on your adventures. All you need is an Internet café to add entries and photos while you're on the road.

When I'm on a cruise with my wife's family and we're in a foreign city for the day, I get off the boat as soon as we dock and hail a taxi. I ask the driver to call his dispatcher and find me a van with an English-speaking driver. Then I negotiate an hourly rate and a pickup time at the dock. The family tours together for a few hours, and then each couple either gets dropped off where they want to spend extra time or returns to the boat (this is great for my elderly in-laws). We get a tailor-made city tour for a much cheaper rate than if we had booked through the cruise line.

For the most comprehensive information regarding travel by train or by ship, check out seat61.com. I've found that the site has all sorts of helpful advice for Africa, Asia, Europe, and the Middle East.

Many computer photo albums use camera date stamps to organize collections. Whenever you're traveling in a time zone that might affect the date stamp (if you're crossing the International Date Line, for example), remember to reset your camera's clock.

Always carry peanut butter. A plastic jar is easy to pack, doesn't need refrigeration, is a great source of protein, and makes a quick, cheap meal when coupled with local bread. (But don't forget to pack a plastic knife for spreading it.)

I'm a gadget freak, and I don't like to travel without things like my digital camera and iPod. On one trip, though, I put my camera down in a crowded restaurant and then forgot to put it back in my bag. By the time I remembered it, the camera was long gone. Now, I attach those kinds of items to my daypack with a lanyard. They're still easy to pull out and use, and they never get left behind.

On my first trip to Cancun, I noticed that my hotel room had a damp, musty odor. The next time I went, I brought two plug-in air fresheners: one for the bedroom and one for the bathroom. This helped tremendously. It was a pleasure to walk in and have a fresh-smelling room. Just make sure you have an adapter, if you need one.

Finding the bathroom in the middle of the night in a strange hotel room or cruise-ship cabin can be a challenge. Leaving the bathroom light on seems wasteful and makes the room too bright for sleeping. My husband and I used to travel with a night-light, but we couldn't always find a convenient place to plug it in. We've recently discovered a better solution: plastic light sticks. They come in several glow-in-the- dark colors and are activated by bending the tube into a circle and connecting the ends. Each evening, we hook one of the loops over the bathroom-door handle, where it provides a gentle glow through the night.

Make your cabin homier by packing a small collapsible vase and a bouquet of flowers.

I reverse the batteries in my portable CD player before packing it in my suitcase or backpack, in case it's accidentally turned on when my bag is jostled. I came up with the idea after arriving at my destination to find that the brand-new batteries I'd put into my Walkman were dead.

Certified scuba divers who take prescription medications should keep a doctor's permission-to-dive statement with their certification cards. On a recent trip to Jamaica, I truthfully completed a lengthy questionnaire about my health, revealing that I have medically controlled high blood pressure and cholesterol. I was told I could not dive without a doctor's OK, even though I exercise regularly, am very fit, and have no other health issues. I now carry a letter from my doctor attesting to my fitness for scuba diving.

Save major bucks by going onto eBay and purchasing coupons and gift certificates that others don't want or can't use for lodging, transportation, food, and admissions. I've found great discounts for airline and Amtrak tickets; car rentals; entrance to amusement parks such as SeaWorld, Disney, or Universal Studios; as well as overnights at many hotels. For example, I bought a $30 savings coupon at SeaWorld for only $1. Simply search for your destination and then type in "coupon" or "gift certificate."

Take along an extra duffel bag for your laundry. As your vacation progresses, throw dirty clothes into the duffel, keeping your suitcase for fresh clothes. At the end of the trip, put a tag on the bag and check it at the airport. This will also give you space in your luggage to bring home souvenirs or new clothes.

During a visit to Mexico City, I was sitting in a plaza near a fountain, watching the locals stroll around in their Sunday best. Nearby, an older gentleman was playing a concertina; his music perfectly framed the scene. I took lots of pictures, but I didn't have a way to capture that music. Now I pack a small tape recorder along with my camera.

Many tourist information offices provide discounted same-day booking services for local lodgings. My husband and I discovered this when we accidentally left a midweek gap in our travel plans between my husband's conference hotel and our B&B in Charleston. Instead of adding another night at either location, we stayed at one of the more elegant inns (normally over $200) for $70, courtesy of the Charleston Convention and Visitors Bureau.

If you even manage to get a cell signal while at sea, your roaming charges will be outrageous. To communicate with your cabinmates, leave Post-it Notes on your door detailing where you'll be throughout the day.

If your vacation spot is a major port of call for cruise ships, plan excursions for the days that the ships aren't docked. Tours will be less crowded, and you'll get to see and do a lot more.

If you have to save receipts while traveling, purchase a plastic coupon holder to help you keep track of them (it'll also protect them). Label each section of the coupon holder by category (hotel, rental car, gas, food, etc.) or by day of the week. The coupon holders are compact and easily fit into a laptop case, purse, or travel bag.

Before leaving on a trip, I print the names and addresses of my friends and family onto clear mailing labels. (All standard word-processing programs have preset templates for creating address labels.) Then, I take the address-label sheets with me on vacation. Since the addresses are already saved in my computer and the mailing labels are adhesive, addressing postcards has become really easy.

I like to bring a Frisbee when I travel. At the hotel, it's a convenient place to collect car keys, loose change, my ChapStick, and any other small objects I normally keep in my pockets. I always know where everything is, and things won't fall off the nightstand. It's also handy to have so you can play Frisbee at a nearby park or beach.

Whenever I'm in a country where drinking or brushing my teeth with the tap water is a risk, I cover the faucet handles in my hotel bathroom with a towel. As a result, I never accidentally turn on the faucet when I'm half asleep.

Batteries for cameras, laptops, cell phones, and other devices can be charged at night in your hotel room. But if you're doing a lot of driving, you might want to buy an inverter to charge them while on the road. Inverters (which plug into the car's cigarette lighter) are small, inexpensive, and can be purchased at auto-supply, variety, or electronics stores.

I take each of my grandchildren on a road trip the summer each turns twelve. The trips range in length from two weeks to a month and require careful packing. I've learned to put our clothes and any snack items we'll need in large plastic bins that fit in the back of my minivan. We each bring a small bag and pack it every evening with items we'll need for that night and the next day: no lugging heavy suitcases in and out of motels or hotels.

We're active travelers but find guided bike tours from companies like Backroads too expensive. Our advice: After rolling into town, ask at a bike shop for the best routes. Better yet, call or e-mail before you leave home (search the Web). We've found group rides and races this way, and have made a lot of friends. We're instant locals!