1-11 stay in the tutorial till it kicks you out. Try to do as many of those quests as you can. Most of them can be done by your self.
11-13 go to Kurn's Tower killing the skillies inside most will be yellow and red.if your not twinked stay here till 15.
15-25 go to Paludal Caverns. on the moon. Group if you want to kill the rogues or the other stuff taking your time, don’t worry about the darkness spell that they can only infect you once.
25-30 go to Marus Seru its almost as good of an area as pc. Kill anything that cons yellow or white to you.
30-40 this is where my memory gets a little foggy, if I remember right the dreadlands is a good place. Or Dulak's Harbor at the beach.
If anyone else has any othere input from 40+ feel free to post.