Yea i spent my time on the arena and the mages guild quests. I would definetly do those while leveling up marksman, cause theres alot of fighting. The assignments are pretty fun, and different per each guild. The mages guild is in depth and has lotsa drama. The fighters guild feels like you are muscle for hire, and go around helping out the little guy. I havent become an assasin or a vampire yet, so dunno bout those. And the theives guild stuff is pretty tricky too, good stuff.
And if you keep killing guards, youll start gaining infamy, and eventually people would recognize you for the evil murderer you are, making it hard to barter. Same, if you are a vampire, people know. Well thats cause you also look pretty hit up. I would recommend hitting up the forts and elvin ruins. There are lots of loot in those, especially forts with human bandits, cause they always wear armor near your level.
I have finished the arena quests, which were fun, I felt like a Gladiator. Every week i fight monsters to keep making cash tho. Im pretty high up in the mages quests, im in the Arcane University, and Ive just only begun the fighters guild ones, im not too high in that.
Here are some screens:
Lewts taken after clearing a fort:
Some Weapons at my house:
My new glass armor look, still need the helm: