Try to keep the amount of communications and IT equipment to minimum. Leave your laptop at home unless you need it for business. With Internet cafes available at every corner of the world lugging a laptop just to keep in touch with your loved ones doesn't make much sense.
Mobile phone can be useful to receive/send 'Hello mum, I just got to Singapore and I am OK' and similar sorts of SMS messages, but try to keep both making and receiving calls to absolute minimum. Your mobile provider will charge you substantial amount for receiving calls if you are roaming on a network far away from your home country, whereas calling home and even calling local numbers is normally even more expensive.
Check your provider's conditions, especially the small print, and remember that conditions often change without this being communicated to the users. Making local calls abroad for example used to be cheap in our case, but at one point we were charged more than 300 EUR for making a small number of local calls overseas as we were unaware of sudden change of conditions.
Your mobile operator probably has roaming agreements with several operators in each country of the world and prices of SMSs as well as calls might vary considerably among the operators whose networks you are roaming on. It is therefore a good idea diging out roaming on which operators' network will work out the cheapest for you and then manually selecting the network of chosen operator upon arrival.
Good information on GSM roaming including best roaming prices in Europe is available at GSM World website.
Travel adapters
Keep in mind that electrical plugs differ around the world. If you will be using any kind of electrical equipment that needs to be charged you should get a universal travel adapter available in electronics stores and at the airports. Never try to plug-in your equipment into an incompatible socket - it could be life-threatening.
Voltage and frequency of electrical systems around the world differs as well, so you should for example be careful not to plug your 220V/50Hz equipment into the 110V/60Hz socket. If you do so, your equipment will be fried.
World Standards website contains a comprehensive guide to electricity around the word.