I use this for everything from venison jerky to marinating salmon or shrimp for grilling, or smoking salmon.
50% soy 50% water, about 1/3 c. brown sugar for every 2 cups liquid (more or less as I don't ever measure it), 1 T or so black pepper.
I use less water if I cannot marinate overnight as it gets the job done faster.
I sprinkle garlic and onion powder over the salmon/meat pieces before smoking. I do not rinse it, just let it stop dripping and glaze a little before putting in the smoker.
I used to make tuna jerky when I worked on commercial tuna boats and would put a can of beer in a large batch of jerky that I simply sun-dried down in the tropics.