*Requires network connect* You just need to have 10 friends on your friends list that have played the game in any way. They do not need to all be online at the same time or anything like that. Once you have 10 friends with the game and log-in, the achievement should pop right away. Check the leaderboards to make sure you have 10 on that list, as the game may take a bit to update. If you are looking for others playing the game to add to your friends list, check the Achievement Trading Thread HERE.