Start with the right equipment: use an oyster knife that’s short and sturdy with a rounded point tip whose blade will not bend easily. Also, use protective gloves: a pair of heavy-duty gardening gloves will work if you can’t find shucking gloves. At the very least you should cover your hand in a dishtowel. Oyster shells have sharp ridges, so even if the knife doesn’t slip, you can cut yourself if you try to shuck with your bare hands.
Choose oysters with tightly shut shells that feel heavy in your hand. The deeper the cup of the lower shell, the meatier the oyster. Hold the oyster firmly in one hand with the deeper cup of the shell against your palm.
Slip the knife blade between the top and bottom shell near the hinge on the back. You may have to wiggle the knife a little to get it firmly into the shell. The blade should be far enough in that it almost reaches the opposite side of the shell.
Keeping the knife blade positioned so that it is flat and parallel to the edge of the shells, run the knife all the way around the oyster until you get to the other side. Be sure to keep the blade pressed up against the inner top surface of the upper oyster shell to avoid cutting into the oyster meat, but still severing the muscle that connects the oyster to its top shell.
Move the blade back and forth until the top shell gives a little. Then, using a twisting motion, pry the top and bottom shells apart. Be gentle yet firm. You don’t want to jerk the oyster or force it because that might spill the oyster liquor.
Once the top shell is completely off, move the blade underneath the oyster meat to cut it free from the bottom shell. Then, tip the oyster from the shell and let it slide down the back of your throat!