Crucial to the success of your assignment abroad is researching your destination thoroughly. From a safety and security perspective get a good understanding of:
Political situation: this can vary from country to country however, even if the way the country is governed is different to what you are used to, you are often protected from this as an expatriate.
Economic situation: understand the currency, how it compares to your own and if it makes economic sense for you to work in that country.
Crime rates: how are rates of crime? Do you need to take more precautions than you would in your home country?
Social norms: how do people dress in public? How do they interact in public? Blending in when you are out of the office often helps when settling in to a new environment.
Living standards: are they similar to your home country? Will your accommodation be of significantly higher standard than the norm?
Communication: Is there high-speed internet and Wi-Fi? How is the mobile phone infrastructure? Being able to stay in touch with home is important while you are establishing yourself abroad and it is easier if you have realistic expectations about how easy it is before you leave.
Expat Network: is there an expat group in your destination country either within your company or in the area you will be living?
To find the above information, use as many sources as you can including:
Your company: should be a font of knowledge for this information, particularly if they already have an office in the destination country. If you are travelling to work in an unstable country ensure your company provide you with an escalation plan should the situation take a turn for the worst.
Online research: search for the topics listed above for your destination country. The CIA world fact book may be a good place to start. Read local publications to get a feel for what life might be like there.
Government websites: review any information from your own government about travelling to other countries.
Online forums: there are a number of online expat forums that are worth joining to post specific questions you may have about your impending move.