Could you guys help with different builds or tips. I've never done a thief. I've always been a good guy warrior type that fights for honor. Also, could you give me tips on RP aspects. Do you do quests or what? I like to justify my reasoning for doing a certain quest. Does your thief character have any motivations besides money? Any advice is welcome. Thanks
I also always start these games as a good warrior, and later play a thief. With Skyrim I did the opposite, but with a difference. I created a "good" thief, or lets call it "rogue". It's not actually a thief.
I decided I wanted to play the game as a good-aligned char, but I wanted the fun of being a sneaky char. I ONLY use these skills: Speech, Archery, Light Armor, Sneaking and Lockpicking. I ignore any other content like alchemy, smithing, enchanting, magic, etc...
As for RP, being a "good" rogue, I don't steal anything from people (don't even have Pickpocket), neither pick anything from shelves, barrels, etc... even if it's flagged "white" (pickable), and even if it's an object I really want, as player. It just sits there, where it is. I only loot dungeons and abandoned forts and castles. I open chests, unlock traps and kill my enemies with an arrow from dark spots I sneaked to. I ignore any quest that makes me steal an object (for instance a book from the Bards College). I also ignore quests which only way of ending it is persuading or intimidating someone into something I consider unfair, like lie to get a ring, just because a Daedra asked me to. I judge the situation myself and if I think the NPC doesn't deserve that, then no quest for me. I mean that I have them in my journal because I started it (without knowing what it is about) but later I realize that it doesn't fit with my char.
So, that's basically my current "thief" character. I plan on doing a real thief later (after I play a mage or warrior), a more evil and selfish one, with those same skills, plus pickpocket, and one handed instead of archery, for using light swords and daggers. In this case I will join both Brotherhood and Thieves guild, something that I didn't even touch with this current character. Will also do a lot of quests that were "undoable" with this char.
I don't know if this helped or not, but just wanted to let you know my playstyle in case it gives you some ideas.
Have fun.
EDIT: Note to all those talking about "missed content". That's why this is a sandbox RPG and not a pre-set storyline where you just pick a class you want to play, and play the same game as any other char type. Here you can stick to being an evil Mage, and later create another char which is a good warrior, that will play different quests, do things differently, have different items, etc... It's not "missed content", it's just playing almost two different games. In my case I have bought all houses in game, but someone could want to roleplay a person who loves Whiterun and does not want to know anything about Solitude, which means that only visits it for business, and leave, so no house there for him, at least with that char.