Line up your jello shot cups or containers on a cookie tray. If you don't have a tray, try using an empty pizza box or something similar.
Spray a little vegetable cooking oil inside the cups. Just a quick spritz is enough. And don't worry, you won't taste anything.
Bring your water to boil. If you're in a super hurry, just make the water hot enough for all of the Jell-O to dissolve.
Either place the hot water in a mixing bowl and add the gelatin, or just add it to your pot. Either is fine. Add ONE box at a time to make sure everything dissolves correctly.
Once everything is thoroughly dissolved, add all of your alcohol. Vodka is best as it doesn't have as much taste as other alcohols, but you can mix in whatever you'd like.
Use a ladle to add the jello into the cups or let cool a bit and use your measuring cup.
Now place the tray of Jello shots in your fridge, NOT in the freezer! It'll take around 4 hours to gel correctly.