I've always done this:
1. Purge
2. Take liquid boil of your choice and put in water. Bring water to rolling boil. If you want shrooms, corn and potatoes, toss them in now.
3. Take equal amount of liquid boil, put in already seasoned water after it's reached rolling boil. Let boil for about 2 minutes to mix thoroughly. Always use 2x what the instructions on the bottle tell you. The instructions are written so that people with delicate taste buds will still buy the product, but so weak that people that want flavor have to double up.
4. Dump crawfish in.
5. Remove crawfish when they start to float.
6. Drain.
7. Dust with granular seasoning of your choice.
8. Put in cooler while still hot (but drained) for 5-10 minutes. The steam dissolves a vast majority of the seasonings, and most of it infiltrates into the bug itself, but enough stays on the surface to get your fingers good and seasoned while you eat.
9. Remove from cooler all at once. Dump on table. They should be hot, but not so hot that handling them burns your fingers.
10. Go to town.
My mom's side of the family resides in the middle of coon-ass country in LA, and several of the people I used to work with when I lived in Houston were from places like LaPlace, Baton Rouge, New Orleans, Venice, Thibideaux, etc. and they all pretty much cook them the same way. Everybody has little variances, but for the most part the above is how I've always seen them cooked and always cooked them myself.
To each his own, I just know that this method has never drawn much in the way of complaints - with the exception of nancy's that can't handle good seasoning and cry because they are "too spicy for my girly little taste buds". We usually laugh at those people and ridicule them mercilessly.
I do know one person that soaked after cooking, but he had everything down to an absolute science in terms of how long to boil and how long to soak and exactly at what temperatures for each so that they weren't overdone. I really couldn't tell any difference in the amount of flavor between his method and the one above to be honest. It really seemed like a lot more effort, which I think was a lot of the point, because this dude liked to show off as he cooked.
