you’ll want points in acrobatics, trickery, and shadow arts (deadly arts if you want to make the most of venoms) what you take in those trees is up to you.
scoompoof is right, go the mists and play around with your gear and such, its free to retrait and change your armour/weapons.
With hidden thief trait I usually pre load caltrops > steal unto a target in the middle of a group then dodge away and use pistol opener resulting on 12 – 18 stack of bleeds on 2-3 people the cripple is a bonus as well . Another idea is to use scorpion wire to pull someone back on the caltrops though its buggy as hell. ThiS is more effective when fighting on points where people tend to cluster and aoe more. Using death blossom on top of caltrops can be also effective especially if they are more focused on killing you than dodging away. Thieves guild elite is also a good distraction and the scorpion wire of the npc works better. For solo encounters maybe try ambush trap as you probably will kite someone as your bleeds do the dmg. I have found it a good tactic vs bunker builds.
