Most profitable farm?

easy z-missions (get a run)-- gold z-coin---> rit E.Tome 13-14k
nick gift....4.5/5k ea or farm the stuff to him and sell
BU..nightmare out from ToA and feather from start island 4K
sell lockpicks...83lp for 100K and sell em for 80lp/100k
u-id gold from raptor/Veatir farming 7 u-id/5k
sell Hammer of Kathandrax (KathSC)
running....
arms are low..powertrade Very well stated. If you're the type of person who can't focus on one task for very long I would suggest testing your luck by doing a few SoOSC's and KathSCs once in a while. There is usually 1 or 2 people also starting a FrostmawSC or RavenSC or 1 of the other billion dungeons. If you have an assassin that is. I really like CD Devilman's suggestions though, they require great patience and time. Believe it or not, even I haven't learnt my lesson. I spend days after days wasting time looking for ways to make money, and I know of ways to make lots of cash I'm just too, effing, impatient lol. I've learned that patience is the key to making money.
Also note that once you have a lot of money, it's easier to make more. Why? Because once you have a lot you know that what you're doing is working, and you continue to do it more and more.