Salt your fish -- more than you think you need to. There is something about a salty, grilled fish cooked over a hardwood fire. Yum! Liberally sprinkle salt over all parts of the fish, including the head, tail and inside the body cavity.
Do not add other seasonings at this point! Most other seasonings, even black pepper, will burn on the grill and taste bitter when you eat the fish. Save the additional seasonings for when the fish comes off the heat.