1. The Tuxedo Jacket — The basic rule of a tuxedo jacket is, if you have even the slightest opportunity to rock one, you should! The trick here is investing in one that fits beautifully in the shoulders and has structure in all the right places. Seriously, when you find the right one, you'll wear it forever.

Mango Tuxedo Blazer, $119.99, available at Mango; Tibi Tuxedo Jacket, $485, available at Tibi.