How can I make a Tiffany box cake for 30 people and what colors do you use for the blue color? Thanks for the help.

Color 5 drops teal 1 drop sky blue. Look at cake serving charts for cake size

Sugarshack has a video Boxes and Bows and it is excellent.
www.sugaredproductions.com

If you look in my pix, I just did one last week with an open offset lid. I used Sugarshack's Boxes and Bows video to help with the paneled box and the lid and found out through trial and error that Tiffany blue is in fact 5 drops of teal with 1 drop sky blue. Good luck!