tactic one: get some friends to attack eto, you need to be level 600+ to do this when eto is almost dead let them give you the kill. then join other servers and repeat the same you will get a high rc count asap!
tactic two: this will take vvery very long, go to the triangle point and keep killing things til your fingers wont work anymore
tactic three: get a private server and get at least 12 friend to join then let them constantly reset and mine the rc
tactic four: use autoclicker this can get you to the top rank asap
and that was all i hope it helped you!