1. Always remember: Less is more.
2. Invest in a backpack with handle and wheels for each of you. It gives you flexibility of use and you can use it as your carry-on luggage.
3. Put everyone in comfy clothes and layers. Planes can be a bit chilly, but then again, maybe yours won't be. Kids tend to get too warm quickly, so layers gives everyone the opportunity to get warmer or cooler when needed. Don't wear jeans or tight-fitting clothes. Those overseas flights can be long and uncomfortable.
4. Pack a week ahead of time and then pare down. You'll likely need only about half of what you originally pack. If you are going to any big cities, you'll be able to find most things you will need (clothes, shampoo, blanket, etc.) Remember though that many areas of SE Asia do not have access to tampons, so bring them with you.
5. Buy a few special toys (mini Etch-a-Sketch, card games, video game). Let the kids pick them out, but pack them away for the flight(s).
6. Pack any prescription medicines, your laptop, a full set of clothes, very basic toiletries and a book into your bag. Kids' bags should include a full set of clothes, toothbrush, snacks and some things to keep them entertained in-flight. Treat this bag as if its the only one that will make it with you.
7. Buy a fold-n-go stroller when you arrive. Don't bring one from home. They are too big and bulky. Or go for a wearable pack for the baby/toddler.
8. Remember to hold on to your checked-baggage tickets and ticket stubs. You may be asked for them at the arrival airport.
10. Carry a purse/medium bag that can be worn over the shoulder. Keep all your passports, itinerary, plane tickets, etc. in here and keep it close. Or use a money belt, if you want to be extra cautious.
11. Don't be afraid to ask for a little help sometimes. Locals will know where the kid-friendly places are.
12. Bring along a disposable camera, or an inexpensive digital camera, for the kids to get photos of what interests them.
13. Try to get the kids to record their impressions via journalling, drawing pictures or recording their stories on the computer.
14. Have fun exploring together!