Worth noting, if you're dual-wielding, you can sneak attack with a bonus action. (Go into your reactions and make sure Sneak Attack is set to always.)
AT is mostly about adding control and utility abilities to the Rogue; options to take enemies out of the fight, and aid/supplement your sneaking. Sleep, Colour Spray, Hold Person, Invisibility, etc, are your mainstays. Your unrestricted spells (ie, ones that don't have to be enchantment or Illusion) should probably be geared towards defence and mobility. (Shield, Misty Step, etc.)