Fresh crabs should feel heavy for their size. You can buy a crab live and boil it yourself; alternatively, ask your fishmonger to kill it for you, or buy it ready-cooked. If buying cooked crabmeat ...
I add a few fresh white breadcrumbs ... Other flavours that go with crab are tarragon, dill and parsley. You can be quite generous with all these herbs as the flavour of the shellfish is quite ...