There are places where people tend to congregate which makes Mesos very easy to meet people just by talking to them.
However, I would suggest not taking this approach by going to the busy places (IE: Banks) and talking to random people; with reasoning for this stemming from the fact that everyone is there.
To make a good friend in a MMORPG it's best to find someone who has a similar play style to you. You'll come across these people in your travels all the time, and will meet them while hunting ferocious beasts or standing in line for the forge.
Just play the game, be nice to people, and good things will come from it. But, no matter what, always treat your friends as you would treat a friend back in the real world.
If you get a reputation for being unjust to your friends that reputation will haunt you for the rest of your playing days, potentially ruining your fun in the process.
Players often get together in the real world after meeting each other in a game. These events are normally called fan fairs, and really show how close some friends can become from meeting each other in a game.