I was trying to level my Genetic and wow i felt like i Hit a Jack pot at zeny earning.I earned like 7 mil in nearly 40-45 mins and Base level 5 level Ups and 10 job level ups!
Here is what i did
Take your Genetic in Geffenia kill all the monsters there the drops are awesome to vend n to sell to npcs also
the Build which i m using on my genetic is for crazy weed means str dex build
weapon best will be doom slayer best attack crazy weed is aoe skill n does like 6k damage there for me to all monster except bloddy night he is little tuff.
this will only be helpful to u in private servers where you get direct wraps to dungens in official server its gona be a leveling place mostly as u will burn the zeny in HP and SP stuffs
and dont forget the sign quest requirement to enter Geffenia!
If Geffenia starts To bore u off then try in Abbey level 2 its also a good exp place zeny will be very low here though