Me and my friend were getting laggy play. What server should I use??
The one with the lowest ping on your server list.
If your friend is close to your location, you guys might get better results by hosting a private server just for the two of you.
how do I do that?
Get the server from here:
http://kaillera.com/download.php
Then edit the .conf file in notepad.
If you only want people you know to join, make it private (settings are commented in the file so it’s easy to setup) then just give your friend your IP if you made it private.
If you don’t have a firewall it’s easy, if you do you might have to mess with opening ports.