Place your fillet skin-side up, and grill for 1-2 minutes with the lid closed. Once grill marks have formed, flip the fish over, close the lid, and cook for another 5-10 minutes, or until the fish is cooked through.
How will you know if your fish is done cooking? This will depend upon the thickness of your filet and the heat of your grill, as well as your taste preference. If you're grilling a two-pound salmon filet that's about an inch and a half thick, it could take about fifteen minutes on a medium-high grill. The trick is to watch it, and check for signs of doneness. When fully cooked, the salmon will flake easily with a fork , turn opaque and feel slightly firm. Once it’s done cooking, remove it from the grill with a wide, flat spatula.