OK first off type /join nulgath
second keep going to the right until you see a tainted elemental
third kill the elemental and take the tainted soul and sell for 13k gold
4 repeat steps 1-3
Also the soul has a 25% drop rate so it's pretty easy to obtain
Well, the forest gold bot should get you a decent amount like others stated previously. If you can find an item that drops often and is worth a lot, you can easily make a gold bot using bot manager in various trainers (Le Bot, Arjmld Trainer, etc)
For now you should just use the forest bot with gold boost and auto-relogin while you are sleeping or doing something else away from your computer.