Over cooking salmon how to prevent
How do you want to prepare it? Grilled, roasted, poached? One thing to remember is that salmon will keep cooking once it is take of the source of heat.
Yes, without knowing your cooking method it's almost impossible to advise.
I find if you cook it in a parchment with a little olive oil and some lemon slices it is less likely to become dry if you inadvertently over cook it.
You want to take it out a bit prior to being cooked through. You can insert the tip of your knife to check where it's at. As mentioned, it will continue to cook out of the oven, but I happen to like my salmon medium rare in any event. For some reference, I cook a 2 1/2 pound fillet on 425 for 10-12 minutes, remove it from the oven, and then cover it in foil and let is sit for 10 minutes, There are also great methods that call for cooking at a much lower temp (250) for a munch longer time.
ChefOno raises an important point. Americans gobble down sushi now more than do the Japanese. But do the USA sushi cooks, working with raw fish, have the expertise to say, spot a parasite in the fish? Maybe some wormlike thing that could ruin your life for awhile?