To begin, it’s important to prepare the grill properly. Many types of seafood tend to stick to the grill, and a tender fillet of sole could be lost between the grates. Clean the grates well, and spray the grates well with a non stick cooking spray. Some fish will need to be 
grilled wrapped in a foil packet, while other kinds of seafood such as shrimp can be placed on a skewer before grilling. When cooking the fish, the grill itself should be very hot, allowing the fish to sear and become firm enough to turn safely on the grill.
Another important tip to remember is to know about the cooking times for fish. Undercooked fish is not good for anyone, and no one wants to make their guests sick. Tuna and swordfish steaks need more grilling time than fillets or shrimp. Plan about 8 minutes for every inch thick of fish. Shrimp will usually need only a few minutes on each side. A fully cooked piece of fish will be firm to the touch and will be flaky rather than wet and soft.
I love salmon on the grill, smothered in veggies…mmmmm