Race leadership is based on overall worth.  This means
primarily spent experience, but prestige as a roleplayer
can influence this as well in a very small way.
Race leaders are the most experienced (and thus well known) 
members of their race.  Having race leadership doesn't mean 
the race leader is necessarily a better person or more powerful, 
but he's well known.  Some races are not particularly numerous, 
and this means that even low level characters may end up being 
race leaders.  To become a race leader, one must journey to the 
temple of one of the original creators of the races, Prometheus, 
and attempt to prove oneself worthy.  Doing so will provide a 
bonus to your race's prime stat.  You must be at least Level 20 
to qualify for race leadership.  This is to show your dedication 
to your race.

HINT:  The race temple to Prometheus is somewhere on Perdow.