Hello.
Baking salmon is indeed a wonderful and healthy choice, but it is very easy to overcook because fish has a low fat-to-protein threshold compared to other meats. To keep it moist, I recommend baking at a moderate temperature of 400 degrees Fahrenheit (around 200 degrees Celsius) for about 12 to 15 minutes, depending on the thickness of the fillet.
To lock in the moisture, you can lightly brush the salmon with olive oil or place a thin slice of lemon and a small pat of butter on top of each piece before it goes into the oven. Another great technique is baking it en papillote, which means wrapping the salmon loosely in parchment paper or foil to trap the steam inside. Always check for doneness by seeing if the fish easily flakes with a fork while still retaining a slightly translucent center.