Always enlist a native speaker
Rather than simply translating mentions via a tool, it is essential that you have someone to monitor who understands the cultural nuances of the particular territory you're working on. It is essential to understand slang which when people are limited to 140 character status updates, they tend to use slang. An example of this is Activia, a yoghurt brand which "contributes to the improvement of digestive comfort" is also used as a euphemism for crap in Spain.
Check how a product is used a territory when selecting competitors to benchmark
We constructed a campaign for a well known brand of cheese spread. In Spain we found it was used as an ingredient in sweet dishes for things like cheesecake, in another country it was used principally as a baby food. We needed to adjust the competitors we tracked alongside our brand accordingly.
Check the brand name doesn't take on a duplicate meaning in a foreign language
Avis, one of Europe's biggest hire car firms, tracked mentions of their brand online across Europe. For most territories their brand name was unique and synonymous with reliable car hire but in France, it also means 'opinion' e.g A mon avis i.e In my opinion. And in Italy, it is the name of a blood donation service. Different queries need to be constructed for each language to keep the data clean.
Keep track of local news, issues and information, celebrities
It is very important to keep track of current affairs, celebrity and where your brand might appear next. Rocco Siffredi a famous Italian actor starred in a campaign for Sixt hire cars. Most of the chat surrounding the brand was around the actor himself. So we needed to disambiguate the two to see the sentiment surrounding the brand separately to the sentiment towards the actor.
Understand the weight of different social networks in each territory
So, for example in France, Skyrock is the second most popular social network, in Germany it's Xing. In Italy, Twitter isn't used in any significant volume. Whichever tool you choose Make sure however you decide to monitor
Don't trust location data
Using location data provided by users can be very misleading. Not only do people frequently make up locations like "The Moon", but they also might use temporary locations.