Hi pippopposto
many factors could help reducing ping, starting from your internet connection, a good bandwidth, a good line quality and if you have a wireless connection a less network users and good coverage would help along with the previous factors, but the main factor is the game server location, the closer one the less ping you may have.
To test your line quality this site helps so much :
http://www.dslreports.com/pingtestRegarding your second question this post will help :
http://www.king-clan.com/viewtopic.php?f=13&t=55