BE SURE - Moving can be extremely stressful, be as certain as you can be that it's the right move for you before you go. If possible visit the country before you make up your mind, don't rely on other people's impressions. Ask yourself if the new culture will really suit you (and your family).
BE PREPARED - ...For anything and everything to go wrong. Don't assume that you'll be able to find the perfect job or house immediately. If possible make sure you've got enough money to see you through the first couple of months at the very least (preferably longer). And to do that you'll need to...
BUDGET - As unglamorous as it sounds, good budgeting could be what makes the difference between a successful relocation and a disaster. Before you go, work out what everything is going to cost during those crucial first months when you're trying to find your feet in a foreign land.
DON'T DELAY - Start preparing as early as possible, just getting all the necessary paperwork in order can take a long time. Make a checklist of everything you need to do!
CHECK YOUR BENEFITS - If your company has initiated your move you may be eligible for relocation benefits. Make sure you ask if they haven't told you already!
HEALTH - Make sure that the country you are moving to has adequate healthcare facilities and infrastructure to support you (and your family), especially if you suffer from a medical condition which requires treatment or medication.
YOUR HOME - Think about what you want to do with your current home (e.g. sell it, lease it, leave it empty) and what kind of accommodation will be most suitable in your new country. If you don't know anyone in the new country who can help find accommodation, consider the services of a relocation agent.
EMPLOYMENT - Will you be looking for work in your new country? If so, consider starting your job hunt before you go (use the Internet!) Will you be able to use your existing qualifications or will a period of retraining be necessary? If you're moving somewhere where they don't speak the same language as you then you should...
LEARN THE LANGUAGE - Few skills will have such a positive impact on your relocation experience as being able to speak, or at least understand, the local language. Getting to grips with the local lingo before you go is a great idea!
PAPERWORK - No matter how insignificant that old document at the back of the bottom drawer may seem now, take it with you, the chances are at some stage you'll have to show it to someone. Moving countries can be a bureaucratic nightmare at the best of times but if you come prepared with the necessary paperwork you stand the best chance of a stress free relocation. Things to think about include birth certificates, wedding certificates, educational certificates, medical certificates (including those for your pets!), etc.