What's the proper etiquette when a Euchre trick is earned?
When I used to play a lot of Euchre the side that didn't call trump would often toss in their cards after taking one trick conceding the rest of the tricks to the caller.

Sometimes all it would take is to show the left bower after the right had been played on the first trick.

Each group has to decide what they are comfortable with, but I think the more you play the faster you will get.