I've always been a big proponent of carry-on luggage for plane travel. It cuts down on time--lines for passengers checking in without checking bags are almost always shorter, and there's no wait for bags to appear once you reach your destination--and lets you keep much closer tabs on your bag. And now several airlines have added another reason to my list: starting this summer, American, United, and USAir will all charge you to check even one bag. (Most airlines already charge for checking a second or third bag.) With airfares already on the rise, this extra fee can add to the cost of your trip.

So now's the perfect time to consider carrying on. Here are a few tips that can make it easier and less of a hassle to bring bags on the plane with you, which, in turn, can take some of the stress out of traveling.

#1: Know your airline's carry-on limits
Most airlines allow you to carry on one piece of luggage and one "personal item," such as a briefcase, laptop bag, or purse. In addition, each carrier limits the size of bags that can be considered carry-ons; usually, bags must fall within certain dimensions, and at least one of your carry-ons must be able to fit under the seat in front of you. If you're not sure whether the bags you're considering carrying on board with you meet your airline's criteria, visit the airline's website and search for "baggage policies," or give the carrier a call.

#2: Use easy-to-maneuver bags
Since you won't be handing off your suitcase to baggage handlers, it's especially important that you choose luggage that's easy to move; otherwise, you'll regret it halfway to the gate. Look for a suitcase with sturdy, smoothly rolling wheels. Upright "wheely bags" with wheels on one of the bag's short ends are a much better choice than older wheeled suitcases with four small wheels along the bottom edge (and an all-but-useless hand strap). If you're carrying a shoulder bag, a comfortable, padded shoulder strap is a must.

#3: Pack judiciously
Traveling with only carry-on luggage means you may not have as much suitcase space as you would were you checking bags, so it's key to pack smartly. This is easier in the summer, when you won't need heavy sweaters, jackets, or other cold-weather gear. My standard advice applies here, as always: do some research on the weather in your destination so you'll know what to expect, opt for mix-and-match basics rather than many different and elaborate outfits, and go easy on the shoes, which tend to be among the heaviest and bulkiest items to pack.

#4: Keep valuables in your purse or briefcase
Even if you follow your airline's carry-on rules to the letter, there's always a chance your bag will need to be gate-checked if the plane's overhead bins fill up or if you're traveling on a small jet with limited bin space. So it's smart to keep your most valuable items--computers, cameras, jewelry, prescriptions, and so on--packed in your one "personal item": the purse, briefcase, or computer bag you'll always be allowed to keep with you when you're on board.

On one trip, I had a connecting flight on a small regional jet whose cabin was too small to accommodate suitcases of any kind, necessitating all of us to check our larger bags at the airplane door. When we de-planed and retrieved our bags in the jetway, the woman behind me called the flight attendant over and told him that the camera that had been in her suitcase when we'd taken off less than an hour before was now gone. Don't take the risk of this happening to you; always, always, always keep your valuables in whatever luggage you're sure will be with you at all times.

If you're traveling by plane this summer, save yourself time, hassle, and money by carrying on your bags instead of checking them. With these four tips, you'll be able to glide down the aisle like a carry-on pro--just as soon as that guy blocking the way in front of you takes his seat.