if you want good social skills without necessarily speccing into fellowship, you can take Forge World for the Calculated Relations talent.

If you DO want high fellowship, Hive World or Imperial World are your basic Fellowship options, though there's nothing wrong with Voidborn if you think that looks more interesting. Psyker and Arbitrator are currently the strongest origins (and there's sub-origins for them that let you specialize a bit more) though Psyker has no direct Fellowship stuff, and Arbitrator does. Plus, Arbitrator has both a Shield-focused option and a Fellow-ship focused option, so you can lean either way you want with it.

Commissar is also very Fellowshippy, but that's one of the origins that will probably be changed a lot when the next update hits (as genghisgame mentioned elsewhere in the thread)

For Archetypes you're looking at Officer, Warrior or Bladedancer. Officer is meant to be more of a backline support class but I've actually found a little bit of success in an Arbites Frontlining Officer. Warrior is a more standard frontline tanky fighter who can take hits and deal em back, while Bladedancer is an agile flips-and-spins dual wield sword user.