You want them dry, dry, dry before dredging. Any moisture on the surface of the fish will cause the coating to lift and/or break during the cook, or immediately after.
You can either dredge the seasoned fillets into the flour (or whatever), and shake off the excess; or use a dredger (which is something like a salt shaker only with bigger holes -- bakers use them all the time for powdered sugar) and shake off the excess.
Shaking off the excess is important. You're only trying to help the fish hold together and develop a little texture on the surface, not make a batter or "crispy" breading for frying. That's a different thing.
Good luck with the fish dish,
BDL