In my experience its always been easiest to make friends by hanging around on the forum and interacting with the forum community. It's fun to get involved in discussions with other users and get to know them. The more people hang around the forum the easier it is to recognize peoples' faces in game and become familiar with them. It's also less awkward to approach a user in game when you both know each other from the forum.
In general though, just being open minded, friendly, and talkitive is a easy way to make friends on here. I've sat amongst random pile ups of folks and had some of my best interractions with strangers just by having small talk about things like food or games etc. It's easy to jump from one coversation into another. Just don't go about expecting so much, enjoy people for who they are.