Seafood cookery can seem a bit intimidating, but it's often a relatively simple process, with much of the dish's success relying on sourcing excellent, fresh products. With a few guidelines and handy tricks in mind, these briny beauties need no longer be relegated to restaurant fare. Keep reading for the breakdown on purchasing guidelines for everything from fish fillets to caviar.
Source: Nicole Perry, Shutterstock 
Whether buying fresh or frozen shrimp, look no further than US and Canadian waters, as the regulations regarding shrimp farming and fishing are extremely lax  in Southeast Asia and many other shrimping regions. Additionally, fresh shrimp should smell briny and sweet , like the sea, never fishy or like ammonia.
Whole Fish and Fish Fillets
Whole fish should have clear, convex eyes; bright red gills; and glistening, taut skin. Both whole fish and fish fillets should smell mildly briny , like seaweed, never pungent or like the scent of the air at low tide. Make sure that the flesh of fish fillets is firm, springy, glossy, and never dried out.
Photo: Nicole Perry
Live lobster and precooked tail meat (either fresh or frozen) are the best bets. If buying live, look for active, wriggly lobsters contained in a spotless tank . Also, make sure to either kill these critters in the cooking process  or dispatch them immediately before cooking, as even an hour of waiting time will deteriorate the lobster's flesh, leading to mushy, unappetizing fare.
Look for crab caught from local waters, as this helps keep down cost and increases the odds of a freshly caught crustacean. Additionally, whether buying live or cooked, choose those that are heavy for their size . Eating crab can be a messy affair; if you'd prefer to remove the meat from the shell prior to serving, follow this process .
Generally, bivalves like clams, oysters, mussels, and scallops should all be purchased fresh. In order to ensure that the bivalves you're buying are still alive, look for those that feel heavy for their size, are mildly briny-smelling (like their other seafood brethren), and have tightly closed, intact shells . Intimidated by shucking oysters? This video explains the surprisingly simple process .
Caviar from the Caspian Sea used to be the benchmark against which all other caviar was judged, but nowadays it's illegal stateside. Instead, look for farmed caviar with snappy (never mushy), larger-sized eggs , and make sure to enjoy it within eight weeks of purchase. Additionally, if you're splurging on this luxury ingredient, consider serving it plain on nonreactive spoons so as to better appreciate its nuanced flavor.