Square Shot Glasses
Pulling shots without shot glasses is like eating sushi without chopsticks. Hopefully you don't have a shelf full of random souvenir shot glasses from college and subsequent vacations, but even if you do I recommend buying the ones the pros use. These square 2-ounce glasses are easy to handle, visually appealing, and they'll slide up next to each other so you have more opening where it counts under the spouts. And they'll double-down in the evening for tequila and a game of Sapo. Sold as a pair.