How to host a [low-stress] clothing swap!

Have you ever been to a clothing swap?!? It's just like it sounds - gather with friends and bring unwanted clothing, and trade with them! I've been to two and just recently hosted one, and it was such a success that I wanted to share my tips and take-aways with you.

How to host a clothing swap (low-stress style!)
I've been to a formal clothing swap, with a long period of gathering/making piles and scoping out before a hard start point when the swapping began, and an informal clothing swap with...