You can get 3 achievements in relatively short time, Party Pooper, It's On Now and Upgraded Access.
For this particular achievement, as soon as you start the level you will be greeted by the hostess (Who is all in white), what you need to do is press Y to examine her when she walks away, then press A to pickpocket her and the achievement unlocks.
You can either do it straight away while she walks around, or a little later into the level she always stands in the same spot by a window just before you go outside to see St John.
Go to 4:15 in the video if you are after this specific achievement.
Hope this helps!