Have you ever wanted to play a song which is written in Drop D tuning, but you didn't have your tuner on hand? Well, this task is actually quite simple, and after using this method several times, you'll find yourself able to do this under a minute. In no time at all, you'll be able to switch between songs with a dropped tuning and a standard tuning quickly and correctly.
Make sure your guitar is in standard tuning. If your guitar isn't in tune, the end result will be less than great. If you're unsure on how to tune a guitar in standard tuning, check out this wonderful instructable, written by builder2.0. Once you're in standard tuning, move onto the next step.