As mentioned, the key to great boil is starting with fresh, live crawfish. Not only is the taste 100x better but you can also control how mild or spicy you want your crawfish to turn out. A boil should be a fun event so picking the rest of the ingredients is really up to you and how creative you want to get.
As a general rule of thumb, you will want 3-4lbs of crawfish, per guest, for your boil unless you have some guests with a big appetite or you are skipping other proteins in your boil, then you may want to lean on the heavier side at 5-6lbs per guest.
The main piece of equipment you will need for your boil is a very large pot. Your pot will need to hold at least two quarts of liquid for every pound of live crawfish boiled. Depending on the number of guests, you could end up with a 60 quart boiling pot!
Lastly keep in mind on where you will be cooking your boil with your new supersized pot. Most people opt for outside, using a propane burner, grill, of even a campfire with a grate.
If you buy from another company verify that the crawfish have been purged or if you can’t guarantee it, make sure to clean those crawfish properly before your boil. If you don’t properly clean the crawfish, you will be eating everything that they have been eating (to put it nicely) and you will taste this in your boil. Your chances of becoming sick also increase.