Are you talking small parts as in small components or parts (like derailleur pulley wheels) or as in fasteners or both?
I always like to see things organized by system (brakes, drivetrain, shifting, etc), which tends to make it easier to direct learners to find their parts and think about their bikes systematically. I'm also a huge fan of layering organizational indicators - so for example, on the bin, having words, coloured text, images, and/or an example part. But this can become overwhelming quickly or quickly become disorganized and just create visual chaos, so it ought to be thought out in consideration of your space and I wouldn't use more than 2 indicators probably.
I'm not a fan of drawers because they seem to always overflow, and then the overflow leads to disorganization and mess.
I remember BICAS having a huge, glorious cylindrical sorter with open bins for small parts and fasteners. They also collected them in rolling carts throughout the day and sorting them was a volunteer task. The most tidy and organized shop I have ever been in.