I'm about to embark on making a Tiffany engagement ring box. Couple of questions I have
- do you typically make the sides of the box ahead of time and let them dry/harden before applying to the cake? I'm assuming this is how you get the sides to stick up higher than the white inside.

-Do most people make the lid using styrofoam covered in fondant?

Any tips would be greatly appreciated. I ordered a large diamond ring paperweight to use for the ring, hopefully it arrives in time!

Sounds like you've got it figured out to me.

I made a gift box cake be4. theres a tutorial 4the tiffany box just scroll 2the bottom:

http://www.perfect-wedding-day.com/tiffany-wedding-cake.html