1. Park with your car nose out.
In the rush to catch the parking lot bus, it's easy to leave an interior light on; I'd guess that more travelers I know have had dead batteries at an airport than in any other situation. If you have a dead battery, facing out will give easier access for a tow truck to hook-up.
2. Leave time to get to economy lots.
If you use an economy off-airport parking lot, plan at least an extra 20 to 30 minutes to get to or from them.
They are often significantly lower-priced than other lots. As a result, they're the best place for economy-minded travelers, especially for longer trips where you're racking up several days' worth of parking fees.
3. Pack essentials in your carry-on.
Recent stats indicate that, on average, at least one bag on every flight is lost or delayed. If there's anything you can't live without, pack it in your carry-on. This is especially true of items that are not easily or inexpensively replaced, such as running shoes.
And you'll get through airport security faster if you pack your carry-on more efficiently. For example, have your quart-size plastic bag with liquids and gels packed in an outside pouch or right near the top of your bag so that you can easily pull it out for screening.
4. Know your hotel information.
If a) your baggage is lost or delayed; b) you miss your connection and will be late checking in; or c) you are going to a destination you've never visited before, you'll want to have complete contact information for your hotel on your person. Before you leave home, print out the hotel's name, address and phone number, and program the latter into your cell phone.
5. Take old currency with you.
Exchanging foreign currency after you've returned home is a hassle, especially since almost no one spends any time in an actual bank these days. If you travel abroad with any frequency, and have any stray foreign currency laying around, take it with you the next time you cross international borders. Then, when you get some local currency, you can exchange the money from any other country at the same time.
6. Save your boarding pass.
Do you usually toss your boarding pass as soon as you step off the plane? You might want to reconsider. Your boarding pass can serve as proof of travel if your airline fails to give you the proper credit for frequent flier miles; this type of problem is particularly common if you're flying on a codeshare partner of the airline in question. Your boarding pass can also be useful as a receipt for tax purposes, particularly if you're self-employed.
7. Know when to use -- and when to skip -- the skycaps.
Skycap upside: You check-in at the curb, lose the bulky luggage and head straight to your gate.
Skycaps don't give you a seat assignment and they cost a few bucks, but they can save time if you have a tight schedule.
If you're running late, the skycaps could get you onto a plane you'd miss otherwise. If it's really tight, there's no guarantee that your bags will make it onto the plane, but some skycaps work near-miracles in this department.
I usually walk inside the terminal and look at both the length of the line for check-in and the clock. If the line isn't too long and I have enough time, I go to the check-in; get my seat assignments, and address any problems with the flight such as delays or cancellations. If the line is long and time is tight, I walk back out to the skycaps, tip them well and sprint for the gate.
Also, if you have plenty of time, but know that your flight is nearly full, and the line is long. Every minute you spend in line is another minute that the window and aisle seats are given away. If you check in with the skycap, then sprint to the gate for your seat assignment, you'll often find that the line at the gate is much shorter than at check-in, and you'll actually get your seat assignment more quickly.
8. Get your seat assignments ASAP.
Every minute you pass without a seat assignment is another minute that your aisle or window seat is given to someone else. Your best bet is to check in online, which can typically be done up to 24 hours before your flight. However, not all airlines allow seating assignments.
9. Mark your bags with an easily recognizable item.
There is an endless stream of nearly identical bags on the baggage carousel. The solution is to mark your bags by tying a colorful ribbon or putting a large sticker on your bags. You won't see other passengers pulling your bags off the carousel to check for their tiny name tags, and you'll be able to see your suitcases come out the door from miles away.
10. Remember your flight number.
Knowing your flight number can make your life easier in small or foreign airports that do not list the full names of destination airports or list by flight number alone.