I have been trying to get a jump on Christmas gifts for once. I took a break to make this box for LOML's daughter. She has a favorite coach that she wanted a gift for.
I used a method that was in one of the mags. This is an end view of one of the sides. The dados are cut for the top and bottom and then the middle dado is cut as part of the lift-off lid joint.
You insert your top and bottom and glue / assemble the box.
Now you can add miter keys, dowels or whatever details you like and sand the solid cube. You can see a walnut cube in the back of the pic with keys but not sanded all the way.
Now use the same dado width that the middle dado was done with and cut just a bit deeper than half way (the spoil is shown with dotted lines and diagonal stripes in this pic).
The two parts seperate and you have a perfectly fitting lift-off lid.
Add a handle or feet or both if you'd like.