I finished a game box insert, my second one, for Agricola (my first insert - for Small World - is
here). Agricola is a fairly standard worker placement game which, as is often the case with worker placement games, has lots of little bits and pieces shared by all players and lots of little bits and pieces exclusive to each individual player. That played a part in how I designed the inserts.
The various card decks for the game are in the blue tuck boxes. I just printed patterns to the correct sizes (
from this template maker) on cardstock paper then cut, folded, and glued as necessary. Everything else is all the 50,000 bits and pieces in various trays and the numerous boards (shared and individual player mats).
The left side of the box is only a single layer deep. Well, the card boxes stack, but close enough. The tray in the top left is room tiles, a shared resource, and is double the height of the other trays. The scorepad is under it but I never use sheets from it as I have an app for calculating scores. So much easier. The individual player trays go on the bottom of the box so that only those needed based on the number of players have to be removed. Everyone just picks a color and gets their own tray with all their supplies and any unneeded ones stay in the box. The sixth tray is a shared good so it will always have to come out.
Another level of trays goes on top of the player trays. These are shared resources so all always have to come out. I divided them into multiple small trays to make it easier to place them around the various boards however works best in any game setup based on table or other surface size and shape, number of players, and whatever else is going on.
Finally, all the boards and the directions rest on top of everything else, going to the top of the box and keeping everything solidly in place no matter how much I shake the box around. Seriously, as long as the lid stays on the box, nothing is coming out of its tray.