Its a good idea if you haven't travelled much before, or at least not with a little one, to do a few "test runs" before going on a big overseas trip. This way you will slowly learn what to take, how your baby travels and how you cope as a family unit.
Make sure you have all your travel plans organised. Go over them over and over again to make sure you are set to go. Are all your taxes included? Do you have transfers or pick up arranged? Is there a cot (also called a crib in some countries) arranged? Will you be in transit long if catching a connecting flight? If so, do you need to take an extra meal for bubs, or will you need the stroller? Are you able to easily pick it up from baggage and if so from where?
The aim is to make an easy, stress free holiday with very few mishaps along the way. For us, I even studied the map of Changi airport so I knew where all the parent rooms were near our flight gates. You might think its a bit extreme, but it came in very handy after a 6 hour flight having a tired baby who didn't sleep and had a very full nappy!
Get travel insurance!! I can't stress this enough. Even if you are planning on wrapping you and your family in pillows for the duration of your stay, get it anyway. The world can be a big scary place, but its even more scary when going into an emergency department with no insurance. There are loads of companies on the internet just dying to take your money. Do your reasearch and go with a well known (international if possible) company. Find out who they are "backed by" and get at least 3 quotes. And make sure you are all on the cover.