A crisp crust can only form on relatively dry meat, so if the outside of your meat is wet or it expels too much juices while cooking, the crispy crust won't be fully formed by the time the interior of the meat is done cooking. You could pat your meat dry, but putting it in the fridge uncovered to naturally air-dry is the superior method.

Put your meat on a wire rack over a pan and let it sit for a few hours, which will make a decent difference, or let it sit overnight and up to 24 hours for best results. Air-drying can also be combined with dry brining, or salting the outside of your meat and leaving it in the fridge overnight so the salt can flavor and tenderize the entire cut.