Found on http://www.food.com/recipe/restaurant-teriyaki-sauce-133751

INGREDIENTS
YIELD: 1 1/2 cups, approx.
1⁄4 cup soy sauce
1 cup water
1⁄2 teaspoon ground ginger
1⁄4 teaspoon garlic powder
5 tablespoons packed brown sugar
1 -2 tablespoon honey
2 tablespoons cornstarch
1⁄4 cup cold water
DIRECTIONS
Mix all but cornstarch and 1/4c water in a sauce pan and begin heating.
Mix cornstarch and cold water in a cup and dissolve. Add to sauce in pan.
Heat until sauce thickens to desired thickness.
Add water to thin if you over-thick it :).
And here’s a Paleo version (that I have yet to try…)
From http://paleonewbie.com/soy-free-paleo-teriyaki-sauce-recipe/
Ingredients
1/2 cup coconut aminos
1/2 cup raw honey
1/4 cup juice from fresh oranges
2 tbs rice vinegar
1 tbs fresh grated ginger
1-2 garlic cloves, pressed or minced
1 tbs sesame oil
Pinch of red pepper flakes
Optional: Add 1 tsp arrowroot flour to make the sauce thicker
Instructions
Combine all above teriyaki ingredients in a saucepan over medium heat
When mixture begins to boil, stir for another 2-3 minutes
Remove from heat
Cool and serve!