In the largest soup pot you have, bring seasonings, beer and water to a boil. liquid should be a little over healfway in your pot since you'll be adding a lot to it.
Once boiling, add the onion and the whole peeled garlic cloves and boil for 3-5 minutes. Add potatoes and sausage and boil another 10 minutes. Add the corn and boil for 5 mote minutes. Lastly add in your seafood and boil an additional 3 or so minutes. If the shrimp are on the smaller side, add in the crawfish first and just boil the shrimp for a minute or so.
Remove pot from heat; scoop out ingredients with a slotted spoon, place on a newspaper lined table or in a big tin pan. Serve with parsely if you'd like along with lemon wedges for squeezing and melted butter for dipping!