The best place to steal all loot and collectibles in a chapter is Chapter 1: Lockdown. This chapter is very short and only contains 60 loot items and 4 collectibles. All of these objects are very close together, and you can easily locate their locations by activating Focus vision. Loot and collectibles will then be highlighted in blue. Make sure to search all lockers, drawers, and safes. You will also have to take some hidden alternative routes and climb up some walls. Some collectibles are hidden behind doors. Thus, every time you open a door, close it behind you, and look to see if there is any loot on the ground. If you miss an object, you can either backtrack or pause the game and select "Load - Chapter Start". In your Journal under "Player Progression - Statistics" you can see exactly how many objects you have collected. You will get the "Obsessive Compulsive" achievement at the end of the chapter and not immediately after finding the final item.