General travel tips:
1) Car seats aren't compulsory in some countries, some people would just hold the baby in their arms when they travel on a taxi. Maybe I'm abit paranoid and risk adverse, but I don't feel safe with that as the baby might fly out of my arms if there's any accident. Better be safe than sorry so I always use a baby carrier and put my son in it during taxi journeys. When he's older I may get those booster seats that he can carry as a back pack.
2) Bring baby food for contingencies. Some people thought they could buy baby food when they get to the destination, but I would bring a decent supply just in case. That's particularly important if you go to less developed countries. We could still get Ella's Kitchen pouches in the countries we visited, but they are like double the price.
In terms of stuff we bought for our trips, we found these really useful:
1) flexible foldable bath
As we don't have a bath tub at the place we're staying, we need a bath tub to bathe our son. This folds up easily and fits nicely in our suitcase. Although it's plastic it feels very sturdy. Looks cool too!
2) Microwave Steriliser Bags
These microwave steriliser bags are great because it's so light and compact, and fit into any microwave ovens. I know some people would use steriliser tablets, but because we haven't used those before, we'd rather stick with microwave sterilising than using chemicals to sterilise.
3. Annabel Karmel Food Masher and Bowl
This food masher and bowl set is so handy when you want to mash up banana and potatoes or other soft food for your little one. Light, dishwasher safe, and cheap, and does the job beautifully.
4. BabyBjorn Active Baby Carrier
As mentioned above I use baby carrier when we travel on a taxi without a car seat. Maybe I'm abit paranoid and risk adverse, but I don't feel safe with that as the baby might slip out of my arms if there's any accident. I also used the carrier when we visited places that aren't pram friendly, this BabyBjorn active carrier has a decent back support which I think is more comfortable than other models. The carrier seems well designed and well made, and I didn't have to worry that I might drop my son. He also seems comfortable and fell asleep fine in it. The baby can face you or face the world, I usually let him face me when I want him to fall asleep.