When you see an item on a shelf or table in a store or house where there are too 
many people around to steal it, walk over to the item, get it in your 
crosshairs, and press R3 to pick the item up. Then, take the item to an area 
where no one is, drop it, and steal it. For example, use the Bottle Cap Mine in 
the Craterside Supply on the work bench, pick it up, then drop it at the end of 
the desk to the right next to the two metal boxes. Enter Sneak mode, get next to 
the desk once your indicator says hidden, and steal it.