I got 2 things that can help you train in the thieves guild 1. after completing any part of the quest(?), talk to the guild master about thieving from the mark 1 again. after you do it, teach him, and you'll get 2k thieving exp 2. after you knock out a coshing victim, you can get up the 3x the exp* you get for looting him if you're fast enough * it seems the exp you get from coshing depends on your thieving lvl