you cook them kinda like you boil shrimp...
the way I do it is bring my water/spice to a boil...drop the crawfish in, bring back to a rolling boil, turn the heat off and let sit for 10-12 minutes...
if you want potatos and corn on the cob with them, put the potatos and corn in first when you start to boil the water/spice then when it comes to a rolling boil put the crawfish in, bring back to a rolling boil, turn heat off and let sit for 10-12 minutes...
I use Tony Chachere's More Spice blend seasoning and add a little extra cayenne powder to it...
crasfish season is normally February to June depending on where you are and how much you want to pay for them...the ones I had Tuesday were 7.50 a pound...at the height of the season, they are somewhere around 3-4 a pound.....this is already prepared...
when cooking them yourself...make sure they are alive and not on ice or frozen....