I've seen forum posts where folks grumble about leveling Thieves Guild and how unpleasant it is to grind it out doing the daily Tip Board quests. I agree. Here is a way to make that part of it easier. (I stole this info from another post, incidentally, but it is presented here in greater detail.)
1. Go to Daggerfall harbor and loot the two boats. They are unguarded. You should only have to do this once...to kickstart this process.
2. Find a fence. Sell the mats, weapons, and armor. Launder everything else and keep it in your inventory. These are the "clean (laundered) household items" you need for step 4.
3. Go to the Tip Board in the Outlaw's Refuge in Abah's Landing.
4. Hit E (to bring a heist up) and Alt to close the board (You may have to do this many times) until you get the tip that begins "Esteemed thieves, I need your help." Accept that one. You will receive the quest called The Covetous Countess.
5. You will most likely already have three items that meet her criteria from looting the two boats. If so, the quest will immediately update to "Deliver Clean Items to Client in <whatever town the Countess is in>.
6. Deliver the items to the Countess.
7. Return to Kari in the Outlaw's Refuge. She will will give you a reward that includes a bag of laundered goods. Open it.
8. DON'T SELL THE LAUNDERED GOODS. Keep them in your inventory. The next time you get this quest, you will once again already have the items she wants and can proceed straight to the Countess, then back to do it all over again. Takes about five minutes. Much quicker and easier than trying to pickpocket 30 townspeople.
There are probably some nuances and details I'm missing, but this is the gist of it. You don't get as many stolen goods to help you level Legerdemain, but you can still loot houses and such to do that. Much easier than navigating through the buggy, inconsistent mechanics of trying to pick pockets.