yah umm i just made my character and he is a sith and he needs a Sith master to train him in there ways and the force, so anyone wanna be a kaleesh's master
Having a Sith Master is not the only way to advance int he Sith ranks. You can do favors for Lords and marauders that will gain you prestige. You can also hold Tournaments and whoever wins gain a rank.
Training is also different. The more you use a power the better you become. So technically you can train yourself through RP.