Here are the steps I use when frying fish.
1. Dry fillets
2. Cover fillets in flour, shake off excess.
3. Place fillets in your egg wash, coat evenly both sides.
4. Cover fillets with your batter mix.
5. Place fillets on plate and put in refrigerator for 30 min.

Before frying fish, make sure your oil is at 375 degrees.
When you put the cold fillets into the hot oil, the batter will instantly seal and you should have a perfect coating around your fish.