For me, the arc where Ainz tries to blend in with the human society while secretly being an undead overlord is really interesting. It creates a lot of comical and tense situations. Another interesting one is when he has to face off against powerful magic - using enemies and uses his own unique abilities to overcome them.
Sure. In the Overlord novel, one of the main story arcs is Ainz's exploration and conquest in the new world. He starts from establishing his base in the Great Tomb of Nazarick and gradually expands his influence. Another arc involves his interactions with different races and kingdoms, like dealing with the humans, elves and dwarves. There are also arcs about the internal management of Nazarick, ensuring the loyalty of his subordinates.
I think the arc about the exploration of an ancient tomb is really good. There are many traps and secrets in it, and Ainz has to use his wits and power to overcome them. Also, the arc where he tries to recruit new powerful allies among the different races is memorable. It involves a lot of negotiations and power plays.
Well, start by having a clear beginning, middle, and end in mind. Build up tension and conflicts gradually and make sure there's a satisfying resolution.
Not necessarily. There might have been earlier shows that incorporated story arcs, but Babylon 5 is often recognized as one of the pioneers in this aspect.