You can purchase egg separating tools, but those are not 100% foolproof. So I recommend using 3 bowls. One for the yolks, one for each egg white during the separating process, and one for collecting all the egg whites. My process is to separate the first egg, dropping the egg white into a temporary collection bowl. Then add the yolk to the yolk bowl and, finally, move the collected white to the whites bowl. Repeat with the 11 remaining eggs.